I had a wonderful chance to wind up one of my account managers the other day. This is a company from whom we buy a fair pile of kit each year, and as such we have a number of direct contacts who visit us frequently and handle the corporate relationship personally.
Anyhow, the phone rang and when I answered it the person on the other end told me that "X has given me your details" (X is my account manager). He then started to ask me about my company, beginning with "Is this your only UK office?". (Correct answer: "No, it's my only Jersey office you muppet", though I was more polite than that). When I told my account director they were shocked and apologetic; actually I found it more amusing than annoying because I'd love to be a fly on the wall when they went back to the office and started chucking the bollockings around ...
I've not named the company because I've had this kind of nonsense from no fewer than three of my major suppliers in the last few weeks, so it'd be unfair to mention this one specifically. One arm of the company has you in its "Client that buys shedloads of kit and has a personal relationship" pot, and the department next door decides it's going to cold-call you to ask you whether you've considered using them as a supplier.
Note to big vendors: do you ever discuss clients within your organisation to make sure that division A isn't stepping on the toes of division B and giving needless blog material to clients who happen to be tech eds on things like Techworld?