Cancellation of Flat

I have booked under construction flat in March 2017 by paying booking amount of Rs. 1 Lakh. Total flat cost was Rs 60 Lakh including taxes. I paid Builder Rs. 5.19 Lakh in June 2017. GST was effective from 01 July 2017. GST on under construction house was very high and builder refused to offer any ITC either. Builder gave very poor post sales service too. Thus,I went for cancellation in December 2017 after submitting the cancellation letter. Till this date there is no agreement. Then GST on under construction houses was reduced so builder called back and requested to reconsider cancellation with the assurance of better service. So I continued again by giving cheque of 51000 rupees which was encashed by builder. I am still to receive receipt for that. Meanwhile builder kept sending me demand letters which mentioned that I already have copy of the agreement. Copy of draft agreement reached me only in 20 March 2018 after lot of follow up. After reading draft agreement it was understood that this is not 100% commercial building but there is commercial building also. Brochure does not clearly mention commercial building at all. Plus some of the clauses in the agreement are not acceptable but this is registered with Maha RERA. House cost at this stage is around 49 Lakh excluding taxes. So I want to cancel once again. Now builder is saying at the time of filling the booking form it was mentioned in the form that 10% of the consideration will be forfeited in the event of cancellation.. Total money with builder without any agreement is Rs. 5.70 Lakh since March 2018. Can I file case with RERA seeking damage and compensation on the grounds of cheating and harassment by builder???