Thanks @George and @Michael.
I am in agreement with this. I don't want unhappy tenants either. I offered them initially that I will keep $200 for inconvenience as well as cost of turning away other renters These guys turned up to harassment and threatened they will call lawsuit on me etc. When I asked to send me a letter that they wanted to cancel their lease, they won't do that either, despite offering multiple ways in which they could send the letter.
So at this point, they want nothing but full deposit and I am not sure what grounds they may have to get their money back. So I want to ascertain that if legally I am obligated to.
I have also send letter of abandonment by certified mail. I want to pay them back due amount if I can get a new tenant, as long they are willing to cooperate. I believe after 5 days of sending letter of abandonment, I am entitled to re-rent the place, regardless of how I settle with them.
Again, greatly appreciate your responses.