If you have an email ending in @hotmail.com, @live.com or @outlook.com (or any other Microsoft-related domain), please consider changing it to another email provider; Microsoft decided to instantly block the server's IP, so emails can't be sent to these addresses.
If you use an @yahoo.com email or any related Yahoo services, they have blocked us also due to "user complaints"
IJBM: companies that send official-looking letters to trick you into paying money for their services
The most common such scheme I've seen seems to involve car warranties, but others include requests for government documents, which are particularly good for scaring people, because (1) they can make it look like official government business, and (2) they are very skilled at making their mailers look like bills.
Thankfully I think there are laws that force them to disclose that they're not actually government entities and these are not bills, because I've seen them write disclaimers saying that they're not actually affiliate with the whatever they look like they're representing. But these letters are clearly predatory.
If they actually wanted to do business honorably, they'd make their business name far more prominent, but instead they bury it in the middle of the letter or otherwise make it very hard to find. The not-actually-government letters are at least somewhat clearer, but the car warranty letters really try hard to obscure the fact that they're not actually affiliated with the car manufacturer.