Is abandoning a house that was purchased with a bank loan and ceasing to pay the remaining amount considered a correct and rewarded action?

Borrowing with interest to buy a house is impermissible, as it involves consuming usury (riba). Repentance from this sin is achieved through remorse and a firm resolve not to return to it. If returning the house to the bank is a means of having the interest waived, then do so; otherwise, your repentance alone is sufficient.