IOS 11.2.6 continiuos issues on iphone 6

Hi, i am having continiuos issues on my iphone 6 since i did the 11.2.6 update; from my phone that is overheading, my battery training, itunes not restart the song that i am listening to on my car radio, phone freezing, apps not working properly and the biggest of them all, i cant hear incoming calls when someone phones me - i can hardly make out what they say. Phone still new and not older than 6months. Issues started after i did the update