Breaching a purchase agreement of a villa by a developer. What to do?

Dear sir/madam,

I am from Pakistan and a cancer patient. I purchased a villa land from a developer and as per the agreement, they had to give possession after 20% payment but I paid 70% but they did not hand over possession and sent me a demand note of 100% plus more added amounts.

They did not comply with the terms and conditions themselves and kept on putting penalties on me. I am helpless. Maybe they will confiscate my money?!

It is a matter of life and death for me.

Can you help me, please?