A T-Mobile customer’s monthly bill jumped by $80 with no warning and it took weeks of back-and-forth with the carrier to get it sorted out. The case, first reported on Reddit and covered by PhoneArena, is a reminder that device financing credits don’t always show up reliably, even when you’ve done everything right. The customer, who posts as Humble_Fisherman5391, was two months from finishing … [read full article]