problem in final registration

hai,
MY name is k.siva kumar registered for P.C.C and converted into I.P.C.C and continuing my articleship
I completed my ca inter recently , for registration i have taken DD for Rs. 8,500/- but i received a letter from chennai chapter asking for Rs. 1,500 extra as i was converted into IPCC(for IPCC fees was 10,000) ,but in the Final registration Form the fees for Students who are continuing there articles or completed articles was Rs. 8,500,
As i was continuing my articles i was of opinion that there is no need to pay Rs. 1,500 extra .So please help me about what i have to do
thanks in advance