Telkom data is a stuff up

I set my phone to block roaming because I have a Telkom only 10GB bundle with 500MB of all network data. But no matter what I do, the Telkom SIM consumes all network data until that is completed and then it blocks me from using my Telkom only data. So I ended last month with 27GB available but I had to spend R150 to buy all network data. Today my all network data has been renewed and it's already declinining. Why is Telkom using all network data when my phone has blocked it?