It seems your the unreasonable one for wanting a job you paid for, done merely to a competent standard.
Then they turn around and make it as though you're the troublemaker because they're obviously accustomed to the punters accepting their shoddy workmanship, no questions asked.
They know you need the resources of a forensics lab to make a case against them.
They are no different to a shoplifter to me charging for a job they haven't delivered.
Very disappointed for you. It's a towbar FFS.
