Hi TINATO1501,
Thank you for your post and welcome to the forums.
Apologies for the issue you've been having. We are aware of this, and I can only apologise.
Our user @enlli on other posts relating to this has a fix, which in their words is the following: (let me know how you get on)
'Go to: Settings -> mobile data -> SIM Applications (near bottom) -> tap "Roaming" -> tap "Select Mode"
Tap manual -> then choose National.
Mmake sure your numbers are set to the correct format. If not change region to anything other than UK (Settings -> General -> Language and Region -> Region) and then change back to UK region.'
Cheers,
Ryan.