I gave a blank cheque to a loan shark and he bounced the cheque after I paid everything

Before he opens an execution file, you need to serve him a notice to warn him not to use the Cheque and return it back to you.

If he opens the case, you can submit your objection.

The cheque is treated as an independent financial bond, regardless of the reason for which it was concluded unless there is an agreement concluded explaining the reason for the cheque and its number.

Therefore, it is preferable to resolve the matter amicably or to hire a lawyer, which is a costly matter for you.