I recently received a new message saying "calls to this number are barred from your phone", so immediately I went to Google and started looking and got some feedback from EE pay as you go customer which didn't nail it, hopefully this post will help someone out there save time and move on with their similar issue. Good luck
Nutshell is that I got this message because unbeknown to me I had reached my monthly billing cap - I didn't even know I had one but a long business call to non-package destination did that. I probably received a SMS from EE saying I have reached my cap but honestly, I don't read them.
How I fixed it:
I opened myEE app, went to "Contact us" --> "call us" --> "invoices and accounts" --> dialled the pre-filled mobile number and extension and was transferred to the small business team (because I am small business account holder). I was told "no probs, we know what's going on, lets just raise your limit a bit" and (hey presto), I was up and running again.
Tip:
I did this just after 8am when the lines opened and got straight through, I had tried a few times in the days prior and couldn't get through to anyone in my spare time <-- ha "spare time - yeah right"
Hope this helps - it could just be that you've hit your monthly cap without knowing it
