So I have had issues with getting email through to customers of Fusemail. All I get is this relatively useless message from comendosystems.com when I try to send them an email.
<firstname.lastname@example.org>: host xxx-dk.mx1.comendosystems.com[18.104.22.168] said: 550 rejected is temporarily blocked. Contact support  (in reply to RCPT TO command)
Now after some searches on various search engines you find that the domain is owned by comendo.com. So I tried to email email@example.com and firstname.lastname@example.org. Those emails were returned with the same error as above. So I resorted to my very little used Gmail account and decided to send email@example.com asking them to investigate the issue. I received a confirmation email from Fusemail support (so now comendosystems.com has become comendo.com which is really fusemail.com) that they had received my email. The following day I get a reply from Casper at Fusemail that they will not look into the issue because I am not a customer with them. If I want the issue resolved I need to contact one of their customers to have them raise a ticket with Fusemail. Anyone else see how useless that response is?
- If I could send emails to your customers then I wouldn't be trying to contact you?
- If your customers were technical enough to understand the mail issue then they probably would run their own mail server.
- Do you really want me to inform your customers about how you are preventing their potential customers from sending them emails.
- How many people do you really think go through the hassle of trying to resolve an issue like this. Most will just find somewhere else to do their business.
I did end up trying to email one of Fusemail's customers from my Gmail account. Not surprisingly the technical abilities of this customer was below average and only really resulted in added frustration.
2017-10-23 - edit
Removed comment about not using them.
I was successful in getting my server removed from their blacklist. I contacted them through their website using their contact support form https://www.fusemail.com/contact-support/ and they ended up removing my server's IP address as they could see it was an old entry. This leads to a new rant. We have at this point run out of avaliable IPv4 address space, that means that many new servers are using IP addresses that have previously been in use. So in my opinion you probably should auto expire entries in your blacklist. 6-12 months seems reasonable to me considering how many companies create and tear down VPS instances for customers.
On a different note I think it is rather bad that a company that specializes in email can't put in a proper decline message. That message should have clear instruction on how to contact them for further information and it should not require extensive detective work to find out who actually owns the server. These are things that I think people considering Fusemail should know. Several Fusemail customers lost our business because we couldn't get through to them via email.