Strange Signal Issue

[Chris1979]

So, I've got a signal issue that I've not been able to find an answer for. 

Started a new O2 sim-only contract last week. All was good initially with solid 4G connection and voice signal. Switched to e-sim at the weekend...still all good. Yesterday, my number ported in from my old provider. Didn't pay much attention until today when my signal has been patchy (dropping out completely and perhaps getting 1/2 signal bars at best). I've not seen anything other than 3G on the phone all day despite travelling all over Greater London.

I'm now sat at home, where I used to get 4G. My wife's iphone also on O2 is side-by-side getting 4G...I've got 3G intermittently dropping to nothing! I also notice when both phones are turned on, mine struggles to lock onto any O2 signal for much longer than hers.

Having phoned customer services twice today, I've tried resetting network settings, manually entering them, turning the phone on and off, changing Network Selection from Automatic to O2-UK. No difference. Customer services clearly end up copping out and saying "your handset must be at fault" despite the evidence the O2 connection was fine before the number port.

There is blatantly something going on. I'm just within my 14-day cool off period and I don't want to leave but am being forced to!

My phone on the left next to my wifes phone, right.

Intermittent with no signal sometimes.

[pgn]

If you can still flip back to physical SIM, what happens if you swap the Sims between your and your wife's phones, @Chris1979? All that the forum has to offer is in this Guide: How can I sort out my network issues? Hopefully O2 have offered to have it replaced at this stage?