Most problems can be solved by correctly claiming the listing and fixing it yourself - although sometimes this can be a bit tricky in itself, and you probably already know this by the sound of it.
This link may also be of some use - the information there was updated recently:
http://www.google.com/support/places...&answer=176504
My biggest frustration with Google Places (the new name of local business listings) is that it's very difficult to get ranked without a yellow pages listing. If you are in a market where not many have claimed listings and you claim yours and update with lots of details, you will usually get a good listing boost. But if a business isn't in yellow pages it's very difficult but not impossible to go anywhere at all.
Matt
Marketing Web