Commercial law, litigation, contracts, IP, property law
If the work has already been done, and some of it was unnecessary, then it's probably too late.
If the work he has done is okay then I don't think you can make claim, because you don't have any "damages". You'd have to get an appropriate person to inspect the work done to confirm any non-compliance issues.
If there are faults or non-compliances with his work, or if something else was damaged as a result, then the technician would be responsible to fix them up, and the appropriate licenced person would need to do the work.I would think if this was the case and they refused to have the right person rectify then you would have the ability to make a claim. If they are required to be licenced and offer to rectify any issues personally, I believe you have the right to refuse and insist on a licenced person, and then make claim if they refuse to do this.