RERA Giving Extension After Extension

I booked a flat in Guwahati in a joint project between Simplex Infrastructures and GMDA in December 2016. The duration of the project was 36 months, and there was a grace period of 6 months, as per our agreement. That flat was due to be delivered in December 2020 (inclusive of the grace period). However, they have not delivered the flat to date, i.e., even after 39 months. The RERA has given them an extension for 2 years. They are seeking further extensions from RERA. As per the RERA Act of 2016, RERA can give a maximum extension of one year (Rule no. 6). RERA was formed to look into the welfare of the flat allottees. However, instead of looking into the welfare of the flat buyers, the RERA of Assam is working for the builder and promoter. The builder is intentionally delaying the project due to their own fault. They are applying for an extension, and the RERA is providing it. How can we stop Guwahati RERA's malpractice and make them adhere to the rules?