i have no idea what could go wrong with my wireless usb mouse

Any advice would be appreciated.
Just for the unnecessary long backstory. Recently my laptop had one of its coolers broken, so I had to buy a new one to replace it. To search for the new one (and to make sure which one is broken) I had to dissemble the laptop. It caused no problems, I used to clean it before. I took away the broken part, put the pc back together and ran it. It ran completely fine, so I turned it off and went to buy the new cooler.
The guy that sold it to me was my old acquaintance, so he proposed to set the new cooler himself for free. I don't really trust anyone but myself with it, but lmaoo the guy had an electric screwdriver, I didn't want to waste my time with my regular one, so I gave the pc to him. I mean, he just replaced the cooler, it's literally his profession, he's very precise in his work, what could go wrong?? Something did.

Right after that my wireless mouse gone a bit crazy. It turns on and off randomly, or doesn't turn on at all. I checked the drivers, they're fine. I replaced the battery, nothing changed. I went to buy a new one, the problem stays the same.

I went to the guy that helped me to replace the cooler, but well he knows I've dissembled the pc myself before going to him, so he just blames me for it. He's an old man who always knows best. And I don't want to pay him any money for helping with the mouse.

So yeah I'm not sure what could be the problem. I'm not sure if the guy would even be able to damage all the usb ports at the same time, it sounds stupid. I see no correlation whatsoever, though I had no such problem before the latest dissemblance.

So, even if it's just a coincidence, how do i fix it now?... Maybe there is an obvious decision that I don't know about.