Land is not registering by selling party, seller is telling land is in HMDA mortgage and yet release

Hi I am Santosh Kabade from Hyderabad bought a land in outskirts of Hyderabad under HMDA layout about 4 years back. During booking the plot booking sellers mentioned that the plot I am selecting is under HMDA mortgage and it will be released in 6 months and then it will be registered. They have taken 50% of amount for booking of plot and remaining they said, they will be taking at the time of registration. Since then its more than 4 years, I have never received any information or any update from them. I myself constantly calling them and they are not responding and not showing any progress in the registration. Earlier in 2020 when I personally met the seller he said there was a land dispute with the local land loads and it has been cleared because of that it took so long and he apologize and assured us after lockdown we will get your plot registered. But now again when I called him he telling same old things that it is not cleared and now he had challenged me what you can do. Since then I got upset with his behavior and lost my faith on him. Please suggest me what shall I be doing to safe my hard earned money. Thanks Santosh Kabade