Telkom - We'll load what we feel like

I recently started looking carefully at my Telkom bill, the package that i signed up for is being charged by more than R500 per month for additional data. I find it highly improbable to spend 40GB of data monthly. Who authorised Telkom to add on "Data Bonus Bundle Awarded" each month? I have signed nothing on the contract to this effect. I was also charged an upgrade fee when i moved my package to a higher package. I received an email stating no penalties if you move to a higher package. Call centre unable to provide itemised billing for more than 30 days. extremely vexed by this thieving behavior. I expect this resolved ASAP