I spoke to a guy at Apple care once about something with my MBP, and the issue of Mobile Me came up. This is all purely anecdotal but interesting. He remarked that Apple makes "almost no money" on MobileMe and there had been rumors of raising the price because people wanted phone support. This was a long time ago but even if what he said is 1/2 accurate, it would make sense why $99 doesn't get you phone support. They probably feel as through they can help more people with chat vs. phone, considering a tech can have multiple chat windows open at once. In contrast, this is one of several things keeping me from switching to Gmail--no support. Yahoo offers chat support with their Plus membership ($20/yr), however.
I'm not sticking up for Apple on this but just offering some perspective. I've had issues with the service in the past (mostly SMTP timeouts, me.com sluggishness, calendar re-organization, etc.) but I've not lost data on it. Indeed, it could always be better but I'm glad to see the fixes they have made.
To the OP, if you're unhappy with the service, then don't keep it and find something that suits you better. Personally, I've always felt it was a good value when I consider all the stuff the suite includes (esp. iDisk, find my iphone, etc.)