Apartment Registration Query

Hi, my name is Srinivas. I've booked an apartment at Hyderabad (Project: Aliens Space Station) during Dec-2018 and we had a verbal agreement to pay ~40%-50% by own funds and the rest by applying for a loan. I've completed my payments till May 2019 (few payments were made using my credit cards) and when I contacted builder to apply for loan, the builder delayed it and upon further discussion, it was found that the builder had informed that the payments made using my credit card were swiped on a different project's swiping machine for which the builder didn't show any statement for payment made by me for the apartment I had booked. I even reached out to my bank and asked to dispute the transactions, but bank declined that they cannot dispute transactions after 45/60 days. Before applying for loan, we had an MoU done, stating that the builder will adjust the amount paid by credit card during handover and there's no need for me to pay the balance amount (paid by credit card) which was not shown in the payment statement. I had the below queries and i'm confused on whom to reachout: 1. What options do i have in case I face any issue while handover if builder denies the payment made by me? 2. During booking, sales representative of the builder made a wrong promise that the flat will be delivered by Dec-2019. But the flat construction wasn't completed yet and the handover date in AOS is mentioned as March-2021. Recently, the builder had mentioned that the handover would be in May 2021. 3. I was foillowing up since Feb-2020 to check on when the internal work (plumbing, electrical, painting, flooring, etc) would start, but i haven't received any response from them. I feel like I'm stuck with the payment I had done to them and the builder is forcing me to get the flat registered soon. 4. If I go for registration now, will the builder be legally bind to handover the flat by March-2021 as mentioned in the AOS while applying for the loan? 5. To go for registration, the builder is asking me to give a cheque for the payment made by credit card as a security deposit. But, as I have already made the payment, I'm hesitant to give the cheque as I will be in legal trouble if builder deposits the cheque. Please suggest me with your advice in resolving these issues. Thank you.