Phone does not work as it should after update android 7

matko

A month ago i updated my phone to Android 7. At first there were some problems with the battery, the battery would go down very fast and sometimes it wouldn't even charge. Now, since a week or 2 ago, it's like my phone restarts itself, so every time when i'm on my phone it asks for my pin, but doesn't actually restart. Two days ago i (hard)resetted my phone, but it still does those things. Since I resetted it, it's like my phone tries to unlock itself. I have an UMI super with fingerprintscan on the back and when I want to unlock my phone i use this fingerprintscan. When you try to unlock with fingerprint too often, there comes this text on the screen that says: (translated) Too many tries. Try again later. So, now the problem is that I don't even touch my phone and that text comes all the time on my screen. I didn't have these problems when I had Android 6. What can I do?