Can flat owners association collect Transfer Fee on re-sale of a flat

The builder had collected Rs. 75000 as Maintenance Deposit from each buyer. When the builder sold all flats, he transferred maintenance of flats to our flat owner's association, which is NOT registered with Registrar of Societies, and transferred approx. Rs. 50 lakhs to our association. Thereafter, a committee of members (association) carries out activities of repair and maintenance, as required. The association collects annual maintenance charges from all flat owners, which is Rs. 6000 at present. Also, the association decided that if any flat is re-sold, new buyer should pay Rs. 50000 as Transfer Fee. I understand that, since the association is collecting annual maintenance charges and the original buyers have already paid maintenance deposit, the association cannot collect transfer fee from new buyer. Recently we have got name of owners of our flat transferred from Son to Father and got same registered with Sub Registrar. Kindly advise me whether I have to pay transfer fee.