I am having exactly the same problem. I can send texts OK but any incoming are delayed by 24 hours then deliverd as an automated voice call. I have tried a different tx enabled phone but same results. open reach engineer has been here today and to his credit has done everything he could to find someone in BT who actually had heard of this service let alone know how to fix it.
Hi @twobeards, welcome back and I've moved your post to create your own thread.
Are you still on a a copper phone line from BT?
What happens when you send 'register' or 'reset' to 00000?
Cheers
John