Lie and others in a similar position have ended up in a trap created by the mainland's rapid expansion of tertiary education in which schools scramble for students even though some have no financial means to support their study.

'I feel trapped in a maze with no exit. I wasn't even given a chance to show what I've got to offer,' said Lie, who is now working at a karaoke bar as a DJ, earning 800 yuan (HK$925) a month. 'Without a document to prove my graduation, there is no difference, whether you are educated or a street vendor,' he said.

Across the country, many schools are using the same tactics to force students to pay up. Mainland media and internet forums are filled with stories of debt-laden graduates asking for help.

According to Unesco, China has had 'the largest higher education system in the world' since 2003. In the past 10 years, the number of undergraduates and doctorate holders has increased fivefold.

Last year, mainland campuses reported there were nearly 30 million undergraduate students - more than the population of Australia. The gross enrolment rate stood at about 24.2 per cent, a jump from 1999's 10.5 per cent.

Many of these students are from poor families. The sharp rise in student enrolment quickly outpaced government funding for scholarships and student loans, according to Dr Li Jun , an expert on mainland higher education at the Hong Kong Institute of Education.

'Among Western universities, when a student is unable to pay tuition fees, there's no room for negotiation. He or she has to withdraw from studying if no other means of financial support can be acquired. But it's a different story in China,' Li said. 'Tertiary schools here like to have large numbers of graduates, and the system allows students to enrol first and pay the fees just before their graduation.'

Professor Shen Hong of the Huazhong University of Science and Technology in Wuhan , Hubei province, said the central government provided a number of scholarships, subsidies and low-interest loans to undergraduates based on their financial status. 'There are two types of scholarship, with one based purely on merit and the other targeting outstanding students from poor families,' Shen said.

The latter, called the National Lizhi Scholarship, offers up to 5,000 yuan a year to its recipients, which accounts for about 3 per cent of all students. Those who cannot get scholarships can still apply for a national grant - which offers about 2,000 yuan a year. Roughly 20 per cent of students qualify for this.

Apart from direct subsidies, the authorities also offer special loans - via local rural credit co-operatives, banks or financial institutes - to students from poor families. Each applicant is limited to 6,000 yuan in loans per year. No interest is charged during academic years; it begins to compound after they graduate.

Even with all these assistance programmes in place, many still struggle to make ends meet. Tuition fees for most mainland tertiary institutes range from between 4,000 and 13,000 yuan per academic year. Applying for student loans is tedious and difficult.

Some areas of the country have higher percentages of poor students, meaning each one sharing the pot gets less, Shen said.

'We can't rule out the possibility of administrative mishaps that prevent the poorest students who are in need of scholarships or student loans getting subsidies,' she said. 'There is still a lack of a transparent income reporting system on which the loan and scholarship bodies could rely to compile correct income data on the families of students. In mainland China, determining the financial status of underprivileged students is still a problem.'

Lie's case is a typical example.

He grew up in a family whose sole income came from his mother's dole money because she is classified as having a severe mental disability. Lie's father is unemployed.

The family of three had been living on 1,200 yuan a month. Only in recent months has the allowance been raised to about 2,000. The average disposable income in Guangzhou is 1,382 yuan per month, according to the city's statistics department.

After leaving the vocational school in 2002, Lie worked as a telephone operator in several Guangzhou hotels thanks to his good command of English. But he could not stay in each job long and was often the first to be sacked because he had no graduation certificate.

'If I can get my certificate back, I could work as a property manager with all the work experience I have accumulated by now. My salary would be about 3,000 yuan, and that could transform my life from hell to heaven,' he said.

Lie has been working two jobs over the years but earns barely enough to make ends meet in an expensive city such as Guangzhou.

He is still 7,216 yuan away from getting his diploma and also has other debts to clear.

In another example, Wang Junming, 25, owes Guangzhou City Polytechnic 8,160 yuan in unpaid tuition since 2007. Coming from a single-parent family with a physically disabled mother, Wang quit his studies without telling his family for fear of adding extra burden on his mother. But he is still in debt.

Similar stories are playing out across the nation. In Henan , graduates have created an internet post that lists tertiary education institutions that withhold certificates. The list includes Zhengzhou University, Henan University of Finance and Economics and Henan University of Traditional Chinese Medicine.

Last year in July, Xinhua reported that the Ministry of Education had banned tertiary institutions from withholding graduation certificates as a way to force students to repay tuition fees. But the reality is another story.

State media have said those that have withheld certificates must offer their apologies to graduates, but no enforcement has taken place.

Guangzhou activist and lawyer Tang Jingling said institutions had no right to withhold students' graduation certificates.

'Receiving graduation certificates is part of a student's right to education,' Tang said. 'Schools should not link it with unpaid tuition, as that is another civil matter. They should award certificates to deserving students without considering any other factors.'

Li acknowledged the widespread practice of withholding diplomas despite its illegality and blamed it on a lack of monitoring. 'In most cases, one-third of schools' income comes from students, another one-third from the government and the rest is up to individual schools' academic programmes. Sources of funding are tight,' he said.

With rapid expansion of the tertiary education sector on the mainland, an enormous number of students needed to be enrolled in order to meet the intake target and maintain the public image of universities being a path to social justice in the way that they offer opportunities to poor students, he said.

'The large number of students on campus is posing an extremely heavy financial burden on schools. The growth of student numbers is not parallel with the applications for student loans,' Li said.

In December, the Nanfang Daily reported that Yang Yuanyuan , a graduate student at Shanghai Maritime University had killed herself, in a story that spelt out a life-long struggle over tuition and living costs for students coming from poor families.

Her suicide note said: 'Even with acquiring knowledge, it is hard to change one's destiny.'