I have a Pixel 7 and I'm based in the UK so my network provider is Tesco. I'm constantly getting text messages saying "Sorry, your number doesn't support Visual Voicemail, so we can't set it up yet. Please contact your service provider for help". I'm new to Graphene OS this year so am still learning. What I don't get is that the messages come from Tesco and they are the network provider, albeit using the O2 network. That's why I'm asking here for advice before I ask Tesco what to do.
Any help would be greatly appreciated.