Hello Student

Yes, certainly you can cancel your seat in which you have taken admission and have not paid the fees and relieving letter from you. You can cancel your seat and prepare for the next year PGCET  exam. If you have not paid the fees  there is no problem for taking admission in another college after qualifying in Pgcet in the next year. In it you may lose one academic year which perhaps may not be beneficial for you.

Hope this helps.