So I'm going to take T-Mobile up on their newest offer, with the $200 line credit for switching (which will be more than enough to reimburse for the ETF with Sprint). I'm going to bring over my iPhone 6, which Sprint will unlock only once the ETF is paid off. My question is, when will the unlock occur? If I cancel service, and pay the ETF online, will that take immediate effect and my phone become unlocked? Or is there some sort of waiting period? I tried searching for an answer but couldn't really find one, and Sprint's live chat keeps telling me it's unavailable. I've never cancelled a contract early and paid an ETF before, so any insight into how this works would be greatly appreciated!