How do I fix my 16GB iPhone 6 Plus?
I got my first iPhone 6 Plus (16GB) last year in late November. My new phone was working out great until June of this year. I got the camera fixed since it was one of the models with the camera not being able to focus problem. Then, a few days later, it started chashing all of the time, there were typing delays (id type for 30 seconds, none of the keys would pop up, then I'd stop and VERY slowly and glitchy, it typed out my paragraph). The iphone overheated when I simply opened Mail and other basic apps. So I brought it in, and they restored my phone to factory settings. Not only do I hate losing all of my content, but they said I can't restore from my back up. I took a deep breath, and said OK as long as it is fixed. Just three days later, the problems got even worse and more rose to the surface. For example, whenever id try going on Safari, my phone would heat up instantly then crash. So, I brought it in again. They gave me a new phone, and then I thought things would be better now (I DID NOT PUT MY OLD BACKUP ONTO THE NEW PHONE LIKE I WAS INSTRUCTED). No. It was the same problems, plus they ruined my SIM card. I went into the Apple Store 10 times in the past 6 months, and the problems only get worse and worse. Whenever my phone gets an Apple diagnosistic test, one time it said it was my apps (ones that, I promise you, were Apple supported apps like Spotify), and then finally, the 9th and 10th time I come in, they tell me it's the software. I asked them to clarify, and they said it was the memory space (I'd believe that if I didn't delete things I needed on a daily basis and had 2GB of free storage on there). I don't have the money to just upgrade to the newest iphone, but after my father going in himself to talk to one in charge, they said there was a memory case for the iPhone. i bought it immediately, excited to finally have a phone that works! But it didn't work. My phone is still lagging (even as I typed this whole thing out).
I need help to get my iPhone fixed or what I need to do next.
These are all the problems my phone has been having;
random restarts w/out passcode, crashes periodically, typing delay, battery draining, apps crashing, crashes after pressing messages, backkey won't work, missing notifications but not on all other products, cant use touch screen occasionally, home and lock button don't turn on the phone immediately, phone lock delay, random capititilizations
Mail notification stays after being read occasionally, crashes when taking a picture occasionally, when turned sideways on lock screen I can't swipe up to go to camera, apple website major lag, slow service everywhere, huge maps delay, phone crashed 6 times trying to do appointment, making apple watch glitch, late notifications, overheating over simple tasks, can't screenshot
iPhone 6 Plus, iOS 9.1