How to get my t-mobile service to work on my iPhone 5s?

I just got a new iphone today & I already set it up with the SIM card. It says T-Mobile in the left corner & has bars as if I have service but when I go to send a text it doesn't go through or when I go to call someone it just calls T-Mobile. How do I get service? I tried calling t-mobile but their calling hours are over now.

What will I do with my iPhone?

I have an iPhone 32GB. I charge it everytime I reach 25%, sometimes I charge it when it reach to 10%. When I charge it, there are times that I have to unplug it and it only has been charged to 50%-70%. Should I drain my battery to zero? What should I do next?

IPhone 6 Help (Disabling Lock Mode)?

Well okay so I bought an iPhone 6 from Ebay for $450. (Yeah yeah I'm not smart) anyway, when I got the phone in the mail it was good until I turned it on. When I turned it on it said: "This iPhone is lost. Please call xxx-xxx--xxxx." which means that the device is in "Lock Mode" and is completely inaccessible for normal use. This lock program is now a new thing for iOS 7&8. So now everytime it is turned on, the phone sends and approximate location of the device to the original person in which the phone was "bought" from. So apparently the person who sold it to me stole it and that's why they sold it to me for such a low price. So now I wasted all my damn money on a freaking useless brick.
Does anyone know how to fix this or disable Apple's "Lock Mode"? I just don't want to turn on the phone because when I do, it sends my location to the first original owner that the iPhone was apparently stolen from. Does anyone know what to do? I literally spent all my money on this phone and I really want it to be worth it.

Is my iPhone 6 broken or headphones?

A lot of info-> IPhone with case dropped twice on hard surface nothing broken. At first one headphone didn't work the right one with the microphone. Some else headphones both worked on my phone, a brand new pair didn't. Other headphone don't work either with one headphone. Sometimes my Siri or Music would randomly turn on. So what's wrong?

IMessage keeps closing/crashing?

So I try to click on my iMessage and it literally just shows blank lines and no messages and closes by itself? I have an iPhone 5s and I'm currently updated with the new iOS. My friend also sent me a message that restarts your phone in front of your face and turns back on and i don't know if that the root of the problem.