It's not just Wirefly that's killing off its relationship with AT&T: LetsTalk is the next to fall, which suggests that the carrier is doing something to its third-party retail partners that are making them very, very sad indeed. Though we still don't know exactly what's going on, a recent note to LetsTalk affiliates stated that "the primary reasons given for this change in AT&T's business strategy were centered around AT&T cost savings and retrenchment," so it's possible they're reducing commissions paid out to third parties to the point where it's no longer economically viable. We've also heard rumors that AT&T is requiring its partners not to undercut first-party pricing on devices anymore, though that seems downright crazy and somewhat difficult to believe -- it utterly defeats the raison d'être for the likes of Wirefly and LetsTalk and prevents them from offering any value in exchange for the secondary ETFs they levy. At any rate, yeah... unless these guys can get their business relationships patched over in a hurry, don't look for AT&T gear from 'em starting in a few days. No word yet on what this might mean for other web-based mobile retailers -- notably AmazonWireless -- but we'll likely know soon.