I was desperately trying to get through to my GP surgery first thing this morning so I could get an appointment, and tried the number (just a local landline number) a few times in short succession as it was obviously engaged. Then I started to get a recording that said "calls to this number are barred from your phone" and just disconnects. It's incredibly dangerous to do this - I don't have any other phones and getting through to my doctor is urgent.
Virgin Media call centre said it's nothing to do with them and Google Pixel support deny it too. Surely it can't be an NHS doctors' surgery blocking people's calls?? They'd be blocking and distressing patients who need help, every morning at 8am when the appointments open that day.