Fast Karachi - paid fees for SE but need transfer in CS

Hello everyone, I had an aggregate of 67.05, I got selected in every program except for CS, someone told me that sometimes seats remain unfilled even after admission completion so you can talk to management and switch your program, or give the entry test again after 2nd semester. I went to FAST but they told me if the seats are remaining for CS, portal will be updated after 2nd August, but there's nothing updated there. Is there any chance of switching programs after the classes start? Or the only way out is giving re-test at then end of the year? Or should I go to fast physically and ask them rn if they have some seats left for CS, I've heard that if some seats are left, sometimes sifarish and going there can help you. However currently I am selected in SE and I've paid the fees too.

Also, I paid the fees 3 days ago and didn't got my roll number, is there anything to worry about? Or will I eventually get it in a day or two?