Mobile phone users have been warned to look carefully at the overwhelming range of discounts and special offers. The Consumer Council said making numbers portable was a boon because it would force network operators to offer more competitive services. But deputy chief executive Li Kai-ming said customers needed to be wary. 'Many customers [in the past] would have liked to change operators, but they didn't want to have to tell all their friends a new number,' he said. 'This is convenient, but the consumer has to exercise their own discretion. 'There are so many offers that it's difficult to compare exactly what they mean.' Mr Li said people should keep what they needed clearly in mind and not be swayed by offers of extra services. They should also be sure to read all the fine print. 'If someone offers you a free phone but you need to sign a contract with them for as long as 20 or 30 months, then you have to decide whether it's what you want.' This year, the council has received more than 70 complaints about mobile phone services. There were 521 last year.