Guarantee cheque to release gratuity and the way of claiming it back

Hi,

A person had taken AED 150000 loan from a UAE bank. He lost his job and couldn't pay the EMI to the bank on time and his company didn't release his gratuity and demanded surety cheque in order to release his gratuity.

So A took B's cheque as surety for AED 75000. Later A says his case was with the court and he got a clearance letter from the court upon paying some fine and now a becomes a defaulter.

Still, B is receiving calls from the bank since his surety cheque is with the bank.

When A's case is cleared, how can B get back his surety cheque?

How Can B safely come out of this?

Please advise