1. If you pay back the dues and close the account, you shall get the no due certificate and the said property will become free form being mortgaged.
2. However, the Bank will physically return the original title deed of the said mortgaged property to its owner/s only and not to anybody else to avoid any future claim from the original owner or any one of the joint owners.
3. However, the Bank can not treat the said mortgage of your property jointly held with your sister as the mortgage of another loan which stands in the name of your brother in law and sister since the said property stands in your name also.
4. Pay off your loan and get the no due certificate first and then claim back the original title deed to be handed over to you and your sister jointly.
5. If the Bank refuses to hand over the same, lodge a complaint to the Ombudsman of the Bank.