Greyed out wifi and blue tooth not connecting

I've been experiencing this issue for about 8 months. I ordered and replaced both the wifi antenna and the antenna flex cable and neither one of these repairs made any improvement to my device. Not only am I not able to connect to wifi , I am also unable to back up my phone. This has caused my phone to at times go into a factory reset and no longer stores my contacts on my phone, I constantly receive message about my storage being full and I can not update my phone to the newest IOS. I've gone to apple for help and they say I need to replace the intoir phone. I'm wondering if replacing the the antenna interconnect cable will make a difference? Please help, I own my phone! no contact attached and I'd like a resolution which does not result in buying a new iPhone