Some T-Mobile customers got $20 off their next bill because of the outage. One user saved $80 by telling customer service they missed work.

You may need to call T-Mobile to get your credit, it's not automatic.

Verizon gave its users $20 after a big outage in January.

Many T-Mobile users had phone problems on Monday and criticized the company on social media. T-Mobile said sorry but didn't explain what happened.

Mashable asked T-Mobile about the outage, but the company hasn't answered yet. T-Mobile recently reported making $22.7 billion in the last quarter.

Topics include Android and iPhone apps.