How Do I Accept My Ucas Offer Again-please Help Mr Akolawole,londoncool And Othe

I got a conditional offer on april 19 from a school in uk but i have not been able to make replies to the offer,I have fulfilled the 50% tution stuff and have returned the agreement form to the school with my telex copy of the school fees.
The lady in charge of admission now ask me to accept the offer firmly on ucas' website before turning the offer to an unconditional one ,she advised that I should call ucas.

please advise on what I should do

can they still allow me to make relply to the offer?is there any shortcut?I learnt an offer will be declined if not accepted after 14 or 21 days after the offering,please air your views

Mr akolawole,londoncool and others plzzzzzzzzzzz help