invested in a housing society in Akbar Industrial Park, Gwadar

I have invested in a housing society in Gwadar around 2 years back (the name of the project is Akbar Industrial Park, the company name is Engititan Pvt. Ltd., they have some other projects like Akbar Arcade in Gulberg Islamabad), I have paid the required instalments initially on time. Till now, I have paid 30% (PKR 1.4M) of the total value of the project (PKR 4.5M). Now, I need to cancel the contract since I need money, when I asked for cancellation, I was told that we can only refund the amount after completion of the project, for which they didn’t give me any date. Furthermore, they said they will deduct 20% of the total value of plot which comes to around PKR 900,000 (so I will only get PKR approx. 380,000 out of the PKR 1,380,000) which doesn’t seem fair to me as this is an exorbitant amount for which I’m not claiming any good or service in return. If that’s how people made money, it seems like a very good business to me.

I can share the copy of the contract with you, kindly advise me with my claim. Thanks