Supplier takes full payment and does not fulfil

After completing a framing job for me about two years ago, and us acknowledging our failure to resolve payment based on them insisting on full payment for work I have not seen... I finally decided to do this and get my art work back. There was a rate for installation included with delivery. After making payment and requesting delivery I was told I had to wait in line until they were prepared to make the effort to deliver if at all. On asking to speak to David the owner, he refused my call - hiding sheepishly behind his staff on the telephone call. He insisted he was not going to deliver and I should come and collect. Not until I threatened my lawyer collecting them did he agree to deliver within the hour. They dropped the piece off and ran off without installation. I would not recommend them to any client nor would I suggest you pay them until the work is complete and back in your possession.