scam?

I have received an invoice from 'The Geek Squad' for $399.00. I have no idea where this originated? It gives a phone number through which I can cancel, however when I spoke with the person at the other end I was told that they had to access my computer in order to cancel.

This appeared suspicious as well they would divulge my bank or account or card that has been used.

As a final point, I live in the UK and have been told that the UK is in any case not covered by the Geek Squad.