My computer was having trouble. I brought it to a fellow for repair. He charged me $60 and claimed to have fixed it. When I checked it at home, I realized that he did not fix it. He may have tried, but the original issue was still there. He gave me instructions how to potentially fix it. I felt that I paid him and he should take responsibility for the repair. I gave it back to him. He tried fixing it and took a very long time to return it. When he finally returned it, it was totally broken, beyond repair. The original issue was nothing compared to the way it was now. Then it was working in some capacity. Now it is totally dead. Should he reimburse me the $60? What about paying for a new computer? Thank you.
Clearly one cannot give a Psak in monetary disputes without hearing both parties.
In general though, according to the version of events that you describe you would seem to have a strong case for not paying anything, and possibly even for claiming damages suffered. (However, even if your claim for damages would be upheld, it would be limited to the value of your old computer, and would not oblige him to buy a new one.)