After the first recommended exhaustion of the battery - 4.5 days

But now telephony suddenly breaks, the network switches on and off, sometimes data transfer works only, or emergency calls only. This happens every 1-2 minutes – no normal call is possible! Any idea what to do?
The connection options to my PC via USB are incomplete: only the CD drive option shows up as "iAmCdRom" on the PC (Macbook Pro). The MTP or USB storage mode don't!
If I want to flash a new OS - how do I get it there?
AFAIK the OS version isn't up to date but in the menu it says "your system is up to date".
A previous post of mine from 2016.07.30 still has not been approved by the admin - why? If there is no reaction to my posts and they "disappear" I will have to take according action. I hope this is not a scam.