I'm keeping my device since it's almost paidyou shouldn't have. i took this from t-mobiles page, from last year. i wasn't charged anything.
Q: I’m a JUMP! On Demand customer – how do I get iPhone 6s / 6s Plus? How much will it cost to upgrade?
- Upgrading on JUMP! On Demand costs nothing upfront!
- Customers can bring their current device into a local T-Mobile store for a three-point check-up to ensure it’s in good condition and then swap it out for one a new iPhone with no upgrade fees or taxes upfront. And yes, that includes the introductory pricing ($20 a month for iPhone 6s and $24 a month for iPhone 6s Plus – each with 16 GB) while it’s available. Higher memory iPhones may require additional money down.
For. Maybe that's why. Idk