I have an old iphone 4 (yes spare the comments) everything works apart from it wont send or receive picture messages.
Internet works ok as do calls and normal messages.
I have checked all the settings and even re-installed them but nothing seems to make it work.
Not a solution but an observation. My tariff, whilst it includes texts, does not include picture messaging, and these can be chargeable.
To get round this I use WhatsApp when I need to send a picture, as it cheaper and it's not often I want to send, or receive a picture from someone who is not a contact.
You are in the OCEs queue for a response, but hope this gives you an alternative to consider.
You will have to call our mobile customer service teams and discuss this, unfortunately we have no access to the mobile systems on the community.
Use the links on our contact us