I have received a fair few of those calls at my office, I usually have fun with them.
I usually tell them that they are right and we have been waiting for their call to fix it. I ask them if they could wait so I could give them the number for our tech support. They usually hang up at this point but one of them that did hold, I gave him the local police departments number, as our tech support, and asked him to to make sure the issue is resolved and thanked him for helping.
