I moved from another carrier to T-Mobile, using T-Mobile One for a family of 4. A few days later we decided that it wasn't working as well as our previous carrier, so I moved our phones back. T-Mobile charged me $220 (plus setup fees) for 8 days of service. They charged the full $160 for the billing period even though we only used the service for a few days. I haven't been able to track down what the other $60 is supposed to be for.