I purchased a new iPhone5 off of eBay. The photo shows it running iOS6.1.3 and although it is a Sprint iPhone, the price was excellent. It arrived, open box like the seller stated, with the plastic still attached, front and back. Other than being removed from the box, the iPhone is brand new. I went ahead and register with Apple, without issue. I plugged it into iTunes and set it up as a new iPhone. I signed on with my iCloud ID and was set to take it in after the holidays to Sprint and get a cheap line of service installed. Surprisingly, I noticed the LTE in the upper left on the home screen and sure enough, the iPhone is completed activated already. I can send and receive iMessages and phone calls. the internet works flawlessly, as it should for an activated line. I did a little research and see the line was corporately activated back in May of 2013 and probably, simply never used. In checking the EMEI it comes back as 'activated' without issue. So, here is my concern. It appears this iPhone has never been registered before me and never used. Why corporate (based out of New York City) would continue to pay this bill is perplexing to me. I'm tempted to take it into Sprint but afraid somehow that will jack up what is now happening. My question: If this iPhone is simply used and the bill suddenly not paid- is there a warning that is sent via text message first before service is cut off? Also, if this iPhone is registered to me can another entity blacklist this line? What can I do to protect myself from having this iPhone becoming useless? I have no problem paying for this line, I just don't want to do anything that could trigger it getting locked before figuring out how to go about that.