unblock/delist request being ignored

I do not get the names you show when I reverse translate those IP addresses.

When I translate those names, I don't get those IP addresses.

Perhaps you submitted the wrong IPs in your request.

As I have told others, be sure that:

1) The e-mail you send looks like it was written by a human, not a bot

2) You include the error message you received (which includes the correct IP address)

3) You include the history of the IP (e.g. you just got that IP, or you've had it for a while and had a malware incident that sent a bunch of SPAM, but you've fixed that)

4) And, of course, clean up your PITR, MX, etc. information so you look like a legitimate email sender.

I'm curious that source you're using for name and address resolution. When I do a DNS lookup for mx*.rqn.com it resolves to the addresses I gave you, and when I do a reverse DNS lookup the results are also as expected.

From MXToolbox:

MX1:

The bounce message:

As for the history of the IP, this is a new IP range for us because we got a new ISP a couple months ago. The ISP is UTOPIA Fiber, whom you may see listed as the owner of the IP block, as reported by ARIN/ICANN. Please let me know if you have further doubts or questions as to the legitimacy of us as a trusted sender.

I will admit I didn't dig deep or as carefully as I could have when checking your DNS.  I just did standard TRACERT/PING to expose IP/NAME.  I mistyped the name with ping to another valid name and got a different IP.  When I type your names correctly with PING, I get proper forward translation.  I also did NSLOOKUP on them and of course, those show up correctly as well.  PTR checks also look good.  Even the Q&D TraceRoute check now properly returns your names (apparently it took too long to get an answer the first time).  So, my apologies for saying differently, everything now looks proper in the name resolution department.

Did your issues with AT&T customer mail delivery start as soon as you switched to UTOPIA, or did they develop sometime later?  Often you inherit someone else's bad activities to appear on AT&T's RBL.

I appreciate your help. Our mail issues to SBC Global began the exact same day that we switched to our new IP range. Of course, UTOPIA told us this was a virgin IP range...  So far I have my doubts.

"Virgin" IPv4 range?  Not many of them around anymore.  Maybe it was new to them.  I'd put in another request to the abuse e-mail address, following the guidelines above and noting that you've been having this problem ever since you inherited this address and you're not responsible for whatever traffic caused the IP to arrive on their RBL.