I have a refurbished phone and everything was working fine but lately multiple problems occurred.
The first problem I noticed was total unresponsiveness. Randomly, when playing games, the phone just freezes and does not respond to anything, not even the power button. The only way to fix this state is opening the back and removing the battery.
The next problem was the quality of phone calls. Calls with the second SIM became impossible because of very bad connection. I had no problems with connections in the office prior but now the connection indicator of the second SIM is very low most of the time. But it seems to be random, because it can change from almost no connection to more then half full without moving my location.
Battery life became a problem recently. The battery would drop from 40% to shut down within 15 minutes. I guess removing the battery ever so often messed up the internal battery gauge so I tried to reset the battery following this guide (✏ A little Guide to ... Fairphone's Batteries (FP1 & FP2)). It seems to be better already but it’s dropping too quickly still.
While resetting the battery I noticed another problem. Randomly, after restarting the phone, the phone does not recognise any SIM cards, so I had to restart the phone again. Once, only the second SIM was recognised and this messed up all my settings. I even missed a train because I could not go online to buy the ticket. Even the ring tone broke, so I missed some calls but I am not sure if the happend because only the second SIM was recognised or every time the phone does not find the SIMs.
So what can I do? The second SIM is my business number and I cannot afford to miss calls also I don’t want to tell people to call another number because of bad connection. I can do this once but I get bad reputation when this happens multiple times. At the moment I don’t use my phone to make business calls because I fear bad connections so the phone is basically useless for its prime usage.