.....just in case.
My SIM has been working fine in the car for 2 years, and then it stopped allowing internet access last week. The SIM is recognised ok. I know there's plenty of data on it as can check online. I've pulled it out, and shoved it back in
So be interested if you get anything back from the dealer as I'm wondering if at all there's some general kind of problem. If there was, I'd expect there'd be much more noise on the forum though...