Issue with a painting job

[JJ Williams]

We are having issues with a painter. We were talked into paying in full (we know we know!)

they came and started, getting 50% complete and have been finding excuse after excuse to push us back. It has been unfinished for 3 weeks. We told him if it was not done by a certain date we have someone else lined up to complete and will need 50% back. 

They left alot of equipment on site. If they do not pay are we legally able to keep their equipment as collateral?