No issue here? I'd consider it a pretty major issue when tenants refuse to move out after giving notice, and then demand 5K to move.
I've paid a tenant to leave. Glad to see the back of them, I gave them back the deposit despite the damage and intimidation to my relation collecting the rent to get them leave. I had the disgusting task of rebagging about 30 filthy bags of household waste. And I was still glad to get rid of them. The man nearly murdered a child in the street later. They destroyed all the windos in another house and both of them ended up in jail for different legal offences.
I did not address the 5K in my post. The OP now knows the kind of people he is dealing with. So he'd want to be very very careful to do this by the book.