It's decision time, Apple (NASDAQ:AAPL). The chorus calling for an end to your exclusive iPhone partnership with AT&T (NYSE:T) has become a digital uproar.

You'll find most of the complaints on Twitter, as they were when AT&T announced a controversial (but not entirely unfair) upgrade pricing plan in June.

The latest row relates to the iPhone's innovative visual voice mail feature. Users had been reporting that AT&T was lagging in delivering visual voice mail -- the only way to be notified of voice mail on an iPhone. TechCrunch's MG Siegler later confirmed the issues.

"While I was coming home from the office yesterday, I all of a sudden got bombarded by visual voicemails," wrote Siegler late last week. "It was only then that I realized that I had not received one in a while. How long? Since sometime before July 3, apparently. Yes, 2 weeks without a single voicemail."

Old Ma Bell had apparently gone blind.

Whether the issue is now resolved isn't clear. Either way, AT&T is suffering its share of scorn and bad jokes. "Just got a visual voice mail from 1977 from my mom saying my sister was born," joked Michael Buckingham, a software development project manager.

Siegler, for his part, calls the delay and AT&T's lack of disclosure about the problem "inexcusable." I'm inclined to agree, but I'd also love to hear management's explanation. So far, it doesn't seem to have one. Spokesperson Mark Siegel could only tell me that AT&T is "looking into this matter now." He also said the company is adding 20 cities and 2,100 cell sites, and spending nearly $18 billion this year to "improve our wireless and wireline broadband networks."

That's good, but Apple should still be concerned -- if isn't already. Every issue, no matter how small, nicks the iPhone brand. Perception is reality, and the perception -- increasingly, it seems -- is that AT&T is a poor substitute for Verizon (NYSE:VZ) or Deutsche Telekom's (NYSE:DT) T-Mobile, and possibly worse than Sprint Nextel (NYSE:S), whose subpar reputation once threatened to hold back sales of Palm's (NASDAQ:PALM) Pre.

No excuses, AT&T. Fix this problem. Fix the network. Make amends with customers. And do it all on your dime. Apple has choices when it comes to iPhone carriers -- it's time for you to prove that you should be among them.

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