I had the same problem:
I was in France when I made the purchase, and was told a) it was impossible to purchase HD Traffic Subscription directly from the iPhone app (????) b) that the app belonged to Apple, so I should deal with them.... (????) When I pointed out that both these statements were incorrect, the TomTom help desk said something like "We're clearly not getting anywhere. Have a nice day." and hung up.
I then sent numerous emails directly to TomTom (via their site) and then direct emails. TomTom repeated asked me for screen shots of the app, of my purchase, of the version number... but we never got anywhere, until the person who was asing all these questions finally referred me to someone more senior, who finally called me and sorted it out remote on his work station. But this was only after being quite defensive when I told him I was outraged by the treatment I got from the Paris help desk, and the run around I had received up to that point from TomTom. By this time, my outward trip --the reason I had bought the subscription-- was finished!
Bottom line, this company's customer support process is awful, and their prices very high. I am avoiding giving them any more money if possible. A request for an apology, especially in light of the Paris help desk hanging up on me, went unanswered. Giving me 3 months for the price of one was not compensation enough.
PS: When I told the Apple Store i had a "problem with this purchase", I was refunded immediately and first, questions were asked later. Impressive, and in stark contrast.
My advice: 1) ask Apple for a refund for the hassle, and 2) simultaneously persist (via email) with TomTom until the problem is sorted. It can be done, but the "front line" support staff seem to lack the motivation or competence (or both) to act.
