When you are a borrow it is not YOU that forecloses, you default, the lender forecloses.
The seller, in your case, as the lender, would foreclose after appropriate notification.
If you were disavow any intrest in the property through Quit Claim Deed
Quitclaim deed - Wikipedia, the free encyclopedia the lender would not in theory need to pursue the same sort of actions against in foreclosure, though they MIGHT want to enforce the terms of the mortgage depending upon what sorts of default/damages clause is in the actual mortgage documents...
If what you are saying is true, that the property is NOW worth more than what you bought it for you may want to try to sell it. If it sells for more than you owe you could avoid having this ugliness on your credit history, the original seller/lender would be out of your life, you could move on to buy something that you can afford...
Good Luck!