iPhone won't go to voicemail - just rings and rings
I've just realised that if someone calls my phone, it just rings and rings, and never goes through to voicemail. I don't know how long it's been like this - I've had the phone and account for a year but it doesn't get used a lot, though I think I'd have noticed before now if this wasn't working. I can call voicemail from my phone and everything seems to work OK, but someone calling me can't leave a message.
It's an iPhone 8, iOS 14.8. I'm on a prepay account, in case that makes a difference..?
Thanks in advance for any help you can give!