do i pay or no?

i hired a plumber to fix a leak and phantom flush in my toilets. they said the gaskets i had put on weren't sealing properly because they were a little large for the older brand of toilet that i had, and that they would need to replace them to fix the problem.

but when i got the bill, there was a long list of other parts they had changed out: toilet handle, flush valve, etc. and on top of that, they billed me $600. to make matters worse, i can't even use those toilets because the toilet is still flushing and running on their own, so i had to turn off the water supply to save my water bill.

these guys ran up the bill and didn't even fix the problem. am i actually responsible for this bill?