BANGALORE -Flat Cancellation Refund Query (down payment already made, but registration not yet done)

STORY : I have booked a flat in Bangalore (small to medium size local builder I would say) by paying down payment of Rs. 7,84,204 (10% of flat cost which is Rs. 41,94,204 = 1372 square feet super built * 3057 cost per square feet) and whilst processing my loan (got sanction letter but during loan disbursement) I learnt the loan was not processed from the housing corporation as they had reached the limit of loan for that property. Now, I had starting approaching new banks and finance housing corps for fresh loan application. During Loan processing : The flat I booked has false ceiling on top in both bathrooms and it had drain pipe of basin and bathroom going into exterior wall (no toilet drain pipe). In meantime, the person owing the flat on my top floor bought S-type trap toilet commode and working with builders Plumber drilled a hole in the ceiling (inside false ceiling) and in exterior wall and put the drain pipe for the commode WITHOUT asking me or taking my permission. The person who did that was my neighbor in old rental home and he told the plumber that it is my home and you do Toilet drilling and piping. When I came to know this I was unhappy and I did scold the person of top floor and then I said its ok now as the damage is done. All Payments have been made by cheque and in name of builder. Post this, Since the toilet pipe is there via the false ceiling and in future it will surely leak and smell (don’t want the hassle and don’t want to fool the new buyer even if I sell it); I then decided to cancel the flat and told builder that I need to relocate and hence cancelling; he asked if I am cancelling because of the toilet drilling but I said no. He agreed to share the details of breakup with me later checking with his advisor. ISSUE : In-spite of many times calling and follow-up he never told me the amount and once in a call he mentioned 2% he might cut but will check with his advisor (out of Rs. Rs.7,84,204 ) and as well told me he cannot refund till he makes sale of the flat to some other party. When I told him I am unhappy in his approach as he is not telling me what he will refund then finally one day he probably woke up and informed me the details on message that he will cut 8% cost because he has paid tax and he is carging nothing to me for himself (Rs. 62,736 out of Rs.7,84,204 = REFUND will be Rs.7,21,468). As well we agreed that he will send me the detail breakup on email from his personal ID. Again the series of follow-up started and he never picks up calls and only texts sometime he is busy. Once he text that he has already sent me email. I checked but no email is there and then again follow-up started and still no email is there. Once he pickup up my call and said why I need details on email; So I told him that I need it written and not verbal commitment. If he had mentioned already that he sent email he should say that why I need details written.