Calls Dropping out

[SusieA]

Im having great problems with my calls going dead, sometimes as quick as 10 seconds after I answer it.  My phone has 0-2 bars on it nowadays, been like this for about a month now.  Problems with texting too, not receiving them has been an issue, like when I'm waiting for a passcode from the bank etc, and sending, something they just sit there not sent with the wheel spinning.

Tried the sim in another phone, same problem

I thought it might have been the sim, so I ordered a new one, no difference.

I bought a new phone! - still the same, in fact it might be worse.

I have turned it off and on, I have turned all all the features off so its just a "telephone" nothing helps

The network coverage for my area says online that its good for indoors and outdoors, but it doesn't matter where I am, after 10 - 30 seconds the call goes quiet, highly frustrating.  Ive been with 02 for I think 15 years but I'm ready to leave if I can't sort this out.

Any suggestions please.

Thank you

[MI5]

@SusieA 

You can try using wifi calling when at home.

Guide: Do you have poor coverage / signal Indoors? This may help Explain / resolve it 

Also check and report issues with the O2 network app https://www.o2.co.uk/apps/my-network

If you can, try the phone set to 2g only and see if normal calls improve.