My former Internet service provider, OChosting, was recently purchased by a much larger company, Velocity Networks.
As part of that acquisition, they moved my e-mail to some more central server. However, they screwed it up really really badly. The DNS MX records for my domain pointed to an old server, but the CNAME I was using for IMAP was pointing to the old one. The helpdesk was completely useless/powerless to fix the DNS records. (As part of this they were transitioning the old systems to a new management system, ala CPanel, as well. The helpdesk people were only able to deal with accounts that had been transitioned.
Finally I told them they'd not only lose my business, but I'd post my negative experiences here if they didn't get someone to help me quickly. That much they did. But ultimately, the promise that DNS records would clear up when caches flushed never materialized. Two weeks later their servers are still giving out incorrect DNS information. I've been able to access my e-mail by manually editing my /etc/hosts file, supplying a workaround IP address. (I have noticed that their IMAP server has gotten significantly slower since the transition as well. It can take up to 2-3 seconds to delete a message sometimes. Typically it takes about 1 second for the IMAP delete to occur. On my other servers IMAP deletes appear to be "instantaneous".) This doesn't work well for my wife though, and I'm fed up with trying to force feed these guys a clue.
I will point out that I was paying these bozos over $20/month for very modest hosting needs, which is 2-3x the typical market rate. And I'd been doing this for about the last 5 years, with nary a service call in the interim.
Anyway, now I'm making good on my original promise to them.
Anyway, I've been able to recover all my old e-mails (at least the ones that didn't bounce, and who knows how many of those occured!), and I've given my business to Bluehost as of about two days ago. So far, it seems to be going quite well. My e-mail performance seems to be good, and the software they have deployed for CPanel is a bit more sensible as well. (For one, they seem to understand the problem of matching TLS/SSL certificates to hostnames when used for IMAP or SMTP.) I'm also paying $7.95 a month (full year paid in advance) instead of $19.95, and my disk and throughput quotas are much much higher (not that I need them).
I would strongly urge folks considering ISPs to avoid Velocity Networks or any of their affiliates if at all possible. My experience is that they are clueless, and their helpdesk staff are completely hobbled by a combination of restrictions on what they can perform and their own lack of ability.
A big kudos to Bluehost, as well.