Telkom not upgrading data but gets paid

I've been a loyal Telkom customer for years. I upgraded my data from 60gb to 120gb. While I'm paying for the 120gb they are only sending me 60gb. I've been trying for 2 months now to get them to sort this out but nothing. This has been very disappointing to the point that I feel to move to a different network. Telkom doesn't care about their customers!