Cannot be heard when making calls

[Lennoni]

I've increasingly had issues when making voice calls where it is now at the point that every call i make i cannot be heard on. I can hear the other person and to start with they can hear me but within 1 minute the call drops out and they cannot hear me. This is the case in my flat, in the city centre and surrounding area. I've turned on my wifi calls, reselected o2 as my network and restarted my phone but nothing seems to be making a difference. I'm in Bath and haven't seen any issues reported in this area so I'm now at a bit of a loss as what to do!

any help would be appreciated!

[MI5]

@Lennoni 

Have you checked here O2 Service Status

Also check if you have a case or cover on your phone that is covering the mic.

[Lennoni]

Thanks for your reply. I've checked service status and it does say the area is busy and internet connection may be slow but no guidance on phone calls. I have also asked a couple of friends who are on o2 whether they've been having issues and they haven't.

Using a standard iPhone case - the calls connect fine and i sometimes have a normal conversation for a minute or two but i then drops out and I've been told it sounds like I'm "underwater" I've made an Apple Genius Bar appointment but thought i'd check here for any guidance in the meantime!

[MI5]

@Lennoni 

If Apple say the phone is OK I'd pop into your O2 store and get a sim swap done.