How can I get money back for repairs not done right? on 2001 Mitsubishi Montero Sport

Got valve cover gasket repair for my 2001 mitsubishi not done right now the heaf gasket/s are damaged. Mechanic won't fix it and won't return what I paid him, well over $1,000 dollars. Please advice me on what I can do. There must be a law against thieves like him, that run a business without a license. Thank you

Asked by for the 2001 Mitsubishi Montero Sport
First of all if you just had valve cover gaskets replaced, you got ripped off paying $1000.00

Did you have the heads gaskets replaced or the heads redone?
If you did, then he is responsible if head gaskets are damaged. How do you know they are damaged??Does it leak oil, or is there ant-freeze in the oil?