Subscription fees that I never agreed to

Please assist me, I am being bul**** by Telkom, they charged me subscription fees since July and I asked them what are the subscription fees for they told me that my account has been flagged and I will be credited with that amount only to find out that they still invoice me for the subscription fees and I asked them if there is any agreement whether by voice or signature that I agreed to their subscriptions, the consultant couldn’t answer me, so far I have been charged R600+ for those subscription fees, please assist me