NEW YORK (AP) - AT&T is agreeing to pay the federal government $700,000 and offer refunds to customers for mistakenly forcing some smartphone users into monthly data plans.

In late 2009, AT&T began to require new smartphone customers to subscribe to monthly data plans. Existing subscribers with pay-per-use plans or no plan at all had to get a monthly plan when they upgraded to a new smartphone.

The requirement wasn't supposed to apply when subscribers replaced a lost or broken phone through an insurance program or warranty, or if they moved to a different AT&T service area. But a computer error moved those customers into monthly plans anyway.

AT&T Inc. now must offer to restore the older plans and give refunds, which the Federal Communications Commission says could be up to $30 a month.