Wow. That’s not one issue it’s a whole bunch of them!
First question is will you old employer give you an NOC to transfer to a new employer, if not then you may well pack your bags.
Second question. How long have you worked with the previous employer, again if you have not worked there for very long you cannot simply transfer to a new employer.
It also seems you have a serious problem with your previous employer. If they don’t pay you, you cannot settle with the bank (I’m assuming they have stood as a guarantor for you at some point and are financially liable for your debts?). The only way around this is to talk to them, ask them to draw up a reconciliation of your dues and what the bank is owed. Then get them to make payment directly to the bank for what you owe them, and pay the balance (if there is one).
Without getting around the “issues” with your old employer there is no way that they would even consider giving you a NOC for a transfer, and no way that you’d get your passport back.
You will be fined for an overstay of 1 month. If it get to an overstay of about 4 or 5 months then you run the risk of being deported and banned permanently.