Holding property as collateral until the job is done

The guy I was dating was hired to fix the pillars of my house by my dad. It took him a few weeks to get started and he still hasn't finished. As a result the work that he has done is unacceptable. When I asked when he would finish, he said that " he is not going to waste his time doing something that will probably get redone by someone else". He is already been paid in full. Now a month prior to the job, he brought his king size bed to my house and we put it in my room (he was basically staying with me majority of the time). I've been under the impression that the bed would be here to stay. Now we are on the verge of what seems to be a breakup and he says he's coming to get the bed to sell it. Am I allowed two keep the bed until he finishes my pillars?