I'm mad at Earthlink. Or maybe it's mad at me?

Here's the scenario:

1) Someone with an @Earthlink.com email address sends me a message. [Correction: I mean @Earthlink.net]

2) I write back.

3) I get a charming, mock-affable message from the Earthlink spam filter saying that my reply has been blocked. (Sample, with identifying details removed, at end of post.)

I assume this is because my IP address shows that I'm in China. Or because I'm using a wi-fi system with dynamic IP address assignment. Or something. Whatever it is, other email systems are able to cope with it. This bounceback happens whenever someone from @Earthlink.com sends me mail. It does not happen (so far) with anyone else.

Come on, Earthlink. You can do better than this. At least you can give a blanket OK to return mail from addresses your members have already sent mail to. Right?

(Here is what I get x times a day:)

Hi. This is the qmail-send program at cnshasmtp3.maginet.net.

I'm afraid I wasn't able to deliver your message to the following addresses.

This is a permanent error; I've given up. Sorry it didn't work out. [Note to Earthlink: go to hell with this cheesy bogus empathy!]

Connected to xxx.86.93.xxx but sender was rejected.