Following a year-long investigation, the FCC has made AT&T refund smartphone customers that had been forced into upgrading to monthly data plans. The carrier started mandating monthly plans for all new smartphone subscribers in 2009, but some existing pay-as-you-go customers were allowed to keep their plans under a grandfathering policy.

While this policy excluded those who switched to different phones, AT&T said that pay-as-you-go users replacing handsets under warranty or insurance would be able to keep their grandfathered plans, along with customers who relocated to another market. However, several of these customers found themselves unwittingly upgraded to monthly data contracts.

AT&T will now have to refund those customers the extra money charged on top of a $700,000 fee payable to the Treasury. Affected customers will also be able to return to their grandfathered plans, if eligible. The FCC began investigating this case over a year and a half ago, but it's good to see AT&T finally being held to its word.