I've received my Samsung Galaxy S20 Plus, on contract with O2. I am able to send and receive text messages, and I can browse the internet using data. However, anytime I try to make any call to anybody, an error message in red occurs saying "Number not valid". I received my new phone and sim on Thursday 2nd April 2020, (during UK Covid-19 Lockdown) not sure if that would have anything to do with it. I have attempted to call O2, but the same error message occurs. Not sure who else to contact or how to, and how to resolve this issue. My parter got her upgrade on the same day and her SIM / phone is doing the exact same as mine! Please Help
