MobileMe from Apple does not work

My father has 6 Mac Laptops. So I thought it would make sense to use MobileMe to synchronize the addresses between the different machines, his iPhone and his iPad. But what happens was a total disaster. MobileMe kept doubling the address book entries and even worse: They started adding up and mixing address book entries from different people. Do not ask me how that happend but it did. I deactivated MobileMe. My father also went to the Apple Store in Switzerland, Bahnhofstrasse and they where not really interested in helping more then 10 minutes. This is not a service I would expect for such a good Apple customer.