Voice call problems

[eliminator]

Iphone 12 Mini, aprox 12 months old, IOS 16.4 / Mint condition , zero damage.

Making or receiving a ordinary voice telephone call. I can hear the other person clear but the receiving end says my voice goes in and out and sounds robotic and completely unintelligible' 

Voice calls are now useless.

I have tested the microphone on the voice recorder app and the microphone works fine, records and plays back clearly ~ so microphone is ok.

Voice calls via another platform such as whatsapp are clear.

I try checking online o2 problems and the only feedback is for data or 5g etc

I completed a system reset ( wish i hadn't ) but problem is exactly the same.....

Tried o2 "live Chat" and after masses of explaining my situation several times received system error and disconnected 4 times !! 

Am stumped and haven't even finished paid for the phone via o2 yet !!!!

[Enlli]

If it were me I would call into an O2 Shop with some photo ID and get a replacement SIM to see if that is the issue.

I say shop because at the moment the minute you request a replacement SIM online the cut the old one off and you will be without for a few days

[MI5]

@eliminator 

You can check for any network issues here O2 Service Status

Guide may also help Guide: How can I sort out my network issues? 

[eliminator]

Enlli, thank you for your reply & help......good suggestion. Much appreciated. 

[eliminator]

M15, thank you for your reply & help......I'll give that a try. Much appreciated.