Sad to say, your issue is not isolated to TomTom.
The main maps used by TomTom are provided by other sources. The most common providers are TeleAtlas (which seems to provide the maps I get) and Navteq.
In addition to the TomTom MapShare, these sources will accept entries from users. I have submitted updates to both sources, but it does take a while to implement. With Navteq, I can get updates for when my suggestion is acked on. And it has taken 8 months. Sometimes, they come back and say the they had already updated it. But that is usually something that they were close to rectifying.
Unfortunately, this will do you no good, if you are not familiar with where you are. However, the more who update what they are familiar with, the more it will help those unfamiliar.