Can the property buyer hold payments due to continuous delay in the date of handover?

Can a developer force the last payment (on possession/handover) after a 3-4 years delay?

I purchased villas in 2014, fulfilled my obligations and paid 90% each by May 2017(on time).

One villa has now been completed (April 2021) and the developer has been on my neck to pay since; no rest, nonstop calls, emails, penalties, and even threats of termination.

They STILL haven't completed the other villas. I sent a letter for an extension for 6 months and it was denied.

Please advise on what to do.

Thank you!