Again, that person is owed something for their time and work, even if they choose not to charge you for it, to build goodwill.
NOT 580$ for not solving the problem. To me that is thievery.
I agree. For $580, I expect the problem to be fixed. Sounds like he was just house-sitting.
So this guy wants $580 for a problem he didn't fix AND the OP's mom has to pay a new plumber to finally repair it.
I think she should call around and see if there is even this jetter tool, and/or to get a diagnostic from another plumber and to ascertain, if possible, if the first guy did ANY work at all.
I wouldn't pay for a guy to sit around eating bon-bons while I pay for his time.
I'd tell him to renegotiate the bill or take me to Small claims Court. I would not take this to the Arbitration Process, I'd let a judge handle this. I don't know plumbing, but I bet the judge has probably heard too many cases like this and I'd let his ruling stand.
OP, I'm sorry about your dad. This might be an (partially) expensive lesson for your mom to learn she can no longer stay in a mentality of
learned helplessness, which is what happens when perfectly able people weren't taught a level of skills they ARE able of, (like letting the husband take care of all the details,) and then later when faced with the situation on their own, they act helpless, like saying "Just fix it."
The first time it is a natural response. But, unfortunately, she now needs to learn there are certain procedures she do and ways she needs to act, to make sure thieves who spot that kind of situation a mile away, don't get away with taking advantage of a situation such as this. I am not saying this IS one of them, but her own actions contributed to the matter. She just can't act helpless anymore and not ask certain questions, like, was this even a
licensed plumber, and stay to on top of the situation, (watching the man) as some people will
help themselves to her wallet.
She should have taken part of the day off from work to watch if he really did anything, and to have sped him up. If she pays the full amount, he probably walks off with 3 times what she made that day going to work, unless she's a doctor or lawyer. If she stayed at home, his "diagnosis" even though he never originally gave one, might have taken 1 hour. Even with losing time off from work, she still would be ahead money-wise.