Help Heeeelp

[Koreyb23]

Ok. I got my Samsung Galaxy S3 from Ntelos towards the end of June. I got one from them that was originally from Sprint. All they did was flash it. I have a couple if issues. 1: Instead of being able to use my stock messaging app, I have to use one that they downloaded to the phone. Its called Android Messaging or something like that and when I open it, it's called Ntelos Messaging. For some reason it doesn't recieve videos. I CAN use them stock app but it doesnt send MMS messages. 2: I had previously downloaded foxfi on my old phone but it doesn't work on this one. I am guess its because it was originally from sprint. Everytime I turn foxfi on, it says "Turning on sprint hotspot" then it says something like "you may not be subscribed, turning off". Its bs because ntelos never blocked foxfi for me. 3: How come my phone has emojis already on it but I can't see the ones people send me? Is it because i am not really able to use the stock app? Ugh. I just want to be able to do the things I used to. By the way, the phone is rooted by towelroot.