Company stole our vaccum cleaner

Matthew from Zero Degreez came to install an air-con at our house. During this process he used and broke our vacuum cleaner (worth around 3.5k). He said he would take it to the office to fix an bring it back. It has been a month. We have phoned numerous times. At this stage he is not answering his phone anymore and nobody else at the company seems to want to help. Even if he can't fix it, we expect our property to be returned as he has basically ****** it.