Rera karnataka

Dear Lawyers, Thank you for attending my query. I purchased a flat in Bangalore. My payment was delayed one time due to some personal reason and delay from the bank side in processing the loan. Now builder is asking from me delayed interest charges. Also there is a delay from the builder side in handing over the final ready flat to me. He said he has also started the annual maintenance charges from the month of May however my registration is still pending. Also they took more than 6 month for working on the observations which I highlighted to them on my 1st inspection. The property was supposed to be handed over to me on 31Dec-18 but still my registration is pending. I requested to them to off-set my delayed payment charges because there is delay from there side also but they are saying as there is a delay from my side I am not eligible for any compensation to be paid from builder side and hence I must may them the delayed payment interest charges. What shall I do in this case? Thank You!