How can I get refund of 5% margin money paid toward a flat?

Dear Sir,
I wish to withdraw the proposal to acquire the 2 BHK property (of Lodha Builders) admeasuring 1,026 square feet in Thane, for which I have already paid 5% (Rs. 1,62,057) towards margin money due to the following extraordinary circumstances. I have paid 5% margin money (inclusive of booking amount). Please let me know how can I get refund of 5% margin money paid toward a flat due to the following extraordinary reasons?
1. I am not going to get as much increment as he was assured earlier, as part of cost-cutting measures.
2. My salary and perks are subject to downward revision (may be w.e.f. April 01, 2009), if the situation does not improve.
3. I was supposed to get some money amounting to more than Rs. 2 lakh as my share towards selling his parental properties in his home state. But due to some reason or the other, the deal could not be materialized, and there is least chance that it would take place in near future.
4. I won’t get annual bonus amounting to more than Rs. 1 lakh, and leave encashment to the tune of Rs. 50,000 this year.
5. My wife is not going to receive the usual annual bonus and expected annual increment this year.
I wish to withdraw the proposal to acquire the 2BHK property supposed to be completed in Dec’10, as I am not going get annual bonus, assured increment and leave encashment this year due to cost-cutting measures. Again, my wife is also not going to get expected annual bonus and increment this year too due to ongoing financial crises.
They are asking 17.5% payment even if no visible construction has taken place as of February 2009; and even if I have a sanction for 85% of the cost of property.
I had requested to extend the payment date being optimistic of getting my finance on track by Apr’09.But, for delayed payment (they term it payment deviation) even they are asking for interest @18% pa for the delayed payment, even though they say that the possession of the flat may be delayed by 6 months i.e. by Jun’11, which they expect me as understandable delay. After Jun’11 they may give interest a@2%, while I need to pay interest @11% to Housing Finance Company.
For cancellation they are asking 10% of the flat cost that means I need to pay another 5% more, even though there is no visible construction has taken place as of now.
Does it amount to unfair trade practices?
They are asking separate Rs. 1.5 lakh as parking amount also. Please guide me how can I get refund of 5% margin money paid toward a flat?