Consequences of sublease without the approval of the landlord

Hello Sir,

I was staying in an apartment with a friend in Sharjah and I relocated to Dubai before the end of the tenancy. The tenancy contract was in my name.

I wrote an agreement with my friend to transfer the contract to his name or cancel at the expiration.

When the contract ended he could not transfer and refused to cancel, so he started paying by cash to the real estate and owed them a huge amount and they opened a case against me at the municipality.

I went with him and he sent a request letter to the Judge to transfer the debt to him stating that the debt belongs to him but it was not approved.

Now, I have started paying the debt, can I use that his request and our agreement to open a case against him at the police or at the court?

Thank you