No Stupid Questions

I worked out a trade deal for someone to do some soldering for me. I had three devices that needed soldering, and they could keep one for themselves if they soldered the three of them for me. Today I discovered that they didn't even attempt the soldering, they fucked up all three of the devices, such that the soldering job can no longer be done by anyone, and they want me to compensate them for the time they wasted trying to fix them without soldering. I asked them to do the job, in trade for keeping one, because I am ill and my hands won't do fine work any more. I definitely don't want to pay them for not doing the job I asked, which I asked them to do because I couldn't afford to pay someone to do it. The job is still not done and can never be done now. Am I wrong to be angry with them? Do I have to be grateful and compensate them for their time that they wasted not doing what I asked them to do?