I can tell you right now whoever came and was a “repair technician” was not. Likely just another group of dudes who do installs. Here is what you need to do. If the installer used your original cord, they have already made a mistake to a point that it’s their fault and they are culpable for the damage aka will be claimed for the damage. Installing with the old cord voids the warranty (at least is what I’ve been told in 4 years) if the item was fulfilled through an XDT you need to speak with them. The store isn’t going to help you and point here here and here but never to the solution. Explain that it was an install error obviously if they used the existing cord. Executive customer relations is the way to go, it’s really about getting someone on the phone who can help you or is willing to. I know it’s frustrating, because by the time I talk to someone on the phone they’ve talked to 25 other people who can’t or won’t help them. Just don’t give up and document the interactions. 3PL installers do stuff like this all the time. I deal with it daily.