I REFER to Ms Flora Liu's letter headlined, ''An Easter lesson in education'' (South China Morning Post, April 12). The telephone numbers of the Education Department's Sha Tin District Education Office were changed on March 1, including the two numbers (6891020 and 6979198) which your correspondent called. The reason a ringing tone was heard when these old numbers were dialled was that, due to an oversight which the Hongkong Telephone Co Ltd has now rectified, they had not been cancelled at the main telephone exchange. Unfortunately, the girl (a typist) in the Kwun Tong District Education Office who took your correspondent's call was unaware of the change of telephone numbers. I wish to apologise to your correspondent for the inconvenience caused, and to assure your readers that all enquiries at our district offices are expeditiously attended to. For the information of your readers, the new telephone numbers at the Sha Tin District Education Office for enquiries during office hours are 6070470 and 6070462. They can also make use of the Education Department's Automatic Telephone Enquiry Service by dialling 8910088 at any time during the day or night. JOSEPH K. K. TSANG for Director of Education