This reminds me of a call I got a couple of weeks ago. The guy claimed to be from Talk Talk (had my name, address, account # and everything – evidently Talk Talk weren’t entirely truthful about their recent hack) and wanted me to go to the URL he was about to give. Cynical as I am was suspicious and told him where to go. I then called Talk Talk; in the course of that conversation I learned something that seems so obvious but I just hadn’t considered it, and I’m guessing it applies to all the providers:
You will NEVER receive a technical call unless you have arranged it beforehand. If it comes out of the blue it’s a scammer.