how do I fight a mechanics lein

Servpro did work on our home. they want us to pay for work that is listed on the contract but the work was done by others and we paid the other repairmen for that work. example ... they are charging for putting the toilet back in the bathroom but we paid our normal plumber to do the work because the Servpro subcontractor screwed up the floor and acknowledged no experience. that is one example of about 10. they charged $1160.00 to unload a pod that was put on our property and they did not unload it. we paid others to do it because in the long run there was never a need for the pod. charging for a carpet in the bedroom... work never done.. charging for removing and replacing the big tub in the bathroom... work never done.. but they are taking us to court to be paid for work they never did. please advise