Rera case

Dear Sir, I booked a property from UPKAR Builders in Hosur near Bangalore in 2013. The total cost of the project was 32 Lakhs. I have paid 16 Lakhs. Agreement for SALE/SALE Deed and Construction agreement was done in 2014 after I paid half the amount of the project. I was not in Bangalore since then and have been chasing with the builder for the updates on the construction and the outstanding payments. all the communications are on email. I used to call the sales employee every month but they were always rude. most of the time they never picked the call. I am back to bangalore now and have visited the office of the builder, the sales manager asked me to visit the site and they will provide me the update on the revised outstanding as the prices have inflated for the construction materials. I have visited the site, they have constructed the building but the finishing work inside and outside are still incomplete as there was a delay in payments because there was no updates from the builder. I am chasing them for the revised costing and incase the costing is high I have also asked them to provide me the current outstanding so that I can pay the amount and get the remaining work done from my own contractor. I have been chasing them for a month but there is no response from the builders. please let me know what legal action can be done. the project is not registered under RERA, it is registered under HMTDA.