T-Mobile chief executive John Legere is upset about customers stealing data from the carrier. In an open letter on T-Mobile’s site, he writes that starting on August 31, his company will be targeting the 3,000 users who are knowingly stealing more than their share of LTE tethered data.

Legere states that at the heart of the issue are customers with unlimited 4G LTE smartphone plans who have come up with workarounds to steal more than their allotment. He claims that these “thieves” are “downloading apps that hide their tether usage, rooting their phones, writing code to mask their activity, etc.”

Only a small percentage of T-Mobile’s 59 million customers with high-speed tethering are suspect, but they are having an impact on the network. Legere writes that some of the culprits are using as much as 2 terabytes of data in a single month. He doesn’t know what they’re using it for, but says he doesn’t care. Initially customers will receive a warning, but then will cease to have access to their unlimited 4G LTE smartphone data plan. They’ll still have service with T-Mobile, but will need to resign themselves to using its entry-level limited 4G LTE data plan. This solution should ease any network issues.

On the carrier’s support page, it indicates that T-Mobile has developed technology to help detect users that are violating its terms and conditions.

“I’m not in this business to play data cop, but we started this wireless revolution to change the industry for good and to fight for consumers,” writes Legere. “I won’t let a few thieves ruin things for anyone else. We’re going to lead from the front on this, just like we always do. Count on it!”

This action will only affect postpaid T-Mobile customers, not those on Pay in Advance (prepaid) plans or MetroPCS.

Get more stories like this on TwitterFacebook