I am, unfortunately they have more items explaining when they can stop providing services due to some 'legal' issue than due to not paying. Below is a summary of what I found to be relevant. Mind you, it's a loose translation of their general conditions. Saying they'll cut you off if:
- you distribute information that's in conflict with (inter)national laws
- you distribute information that's in conflict with general accepted values
- you distribute information that's discriminating (in any way), including (?) adultpages/MP3/warez/video
- no chatrooms, no irc or irc bots
- their servers may not be the source/mediator for spam, flames or mailbombs
- no form of destabilizing their servers is allowed, including any other type of abuse
As is said somewhere else, they don't have a privacy statement, at least not on their frontpage. In my opinion the last remark says it all, it is their decision wether something might be illegal or in violation.
Anyway, they seem to be a small and possibly quite new company, probably not able to handle a big case of copyright problems. Not that it's a valid defense but probably the truth anyway.
Disclaimer: I'm an XS4ALL customer, and happy with them: expensive but quality