Wow OP, that's something sad that has happened to you. It's not easy to convince that you are the innocent in this case, but do what the others have suggested.
This happened in Norway too, a grocery store chain with the name " Lime " did that enough times! They would swipe your card through one POS machine and deliberately, an " error " used to come up. They then used the original machine for the payment, tricking the customer to believe it was just a fault with the first machine. In reality, they collected your data and Pin code, and would be making duplicate cards afterwards...and well, empty your account.
Banks in Pakistan can be tricky, but stand firm on your case and do not give up. It's people like you who will slowly make life easier for all of us!