Add on Internet Bundles which cannot be explained

Initially, when I took out a contract with Telkom Mobile, the contract was R399 per month and I stipulated on the written contract not to exceed Beyond R50. For the past 4 to 6 months I have received bills of over R1000. Every attempt to contact Telkom mobile via chat has expired because no one contacted me. Finally, I got through to the call centre apparently two data bundles has been added to my account one for R69 and another for R506. I have unlimited wifi at home and work and therefore never need any more data. The call centre person Zethu seemed as confused as myself as she could not see when I have added this. Something fishy is clearly happening at Telkom mobile. I am extremely disappointed and disturbed by these bills as it has had serious consequences for me financially. It would have been a totally different story if I actually used the data.