Telkom unable to let me use the data for which I am paying

Telkom doesnt let me use my 10GB of data available to me (and for which I am paying) when the attached roaming bundle of 500MB runs out. This has been happening for 2 months and somehow the roaming bundle runs out even though my phone is set to not roam and never shows that it is roaming on a tower. Telkom don't seem competent enough to fix this problem.