So far getting the otp from the bank, BT's messaging service and yesterday Amazon delivery sent a message that didn't work.

OK, but when you say "didn't work"...can you clarify?

1. Do you receive a call and have to then respond in the call, by entering numbers on your telephone keypad.
2. Do you make a call and have to then respond in the call, by entering numbers on your telephone keypad.
3. Something else?

When I say it didn't work, that is as discribed in my initial post.
Anyway your options it's Number one that has the problem. But number two works.

It seem to be incoming call that fail.

OK that narrows it down.

If this is happening for inbound calls only then, that's something that Vodafone will need to investigate / check on their Digital Voice service.

Log a support call with Vodafone, and tell them DTMF (telephone keypad dial tones) are not being recognised on inbound calls. It appears that DTMF is working correctly on outbound calls.

Well after 3 1/2 hours online to vodafone, I got them to create a ticket. I had run out of ways to describe the problem. "My DTMF (telephone keypad dial tones) are not being recognised on inbound calls." wasn't good enough.

It had got worse in the last few days as their own texts where not getting through, not even ring the phone. This was explained to them god how many times in that 3 1/2 hours.

They obviously had not grasp the situation as they ended the chat with we'll send you a text and you can follow it up from there. And no surprises, no text.

3.5 hours!! Are you sending them a bill for your time?! (joking) 😭😅

I think they work on the presumption that everyone has a mobile. Otherwise how were they going to send you a text if you don’t have a mobile? 🤔

Oh they had been told three times on that chat I did not have a mobile.

Half way through, it was suggested I ring my phone from my cell to see if it works! My partner was watching and I'm not going to repeat her response!

The will to live was fading very fast.

Thanks for giving me the pointers.

Regards.