Builder is delaying for A-Khata and OC

Hi Sir, I had booked a under contrtuction property in Bangalore 3 years ago. Now it is ready to occupy and I wish to sell it. However the builder is only providing B-Khata for which no bank will give loan as it is not A-Khata. At the time of booking that flat, I had verified the legal aspects with a lawyer and the property has a clear title and Encumbrance certificate is also available till current year.I have demanded Occupancy Certificate from builder but builder is only asking to wait and that he is trying to get OC and A Khata for the property. I have also demanded letter of undertaking from builder but builder is not ready to give a timeframe on the letter of undertaking for obtaining the Occupancy Certificate. If I cancel the deal then builder has a clause that I will forfeit 25% of the amount paid. Should I go ahead and cancel the deal and then approach consumer court as it is a deficiency on builder's part for not providing Occupancy Certificate? Please advise the options to me sir - A Khata and OC is of prime importance to me. Many Thanks.