MTN CONTRACT

Good Day i would like to share my horrible experience with MTNsa and this is the second time they do me dirty. I have a contract with MTN which expired ibn April, before the contract expired i was called by MTN agent reminding me to upgrade the contract before it expires I did upgrade online but the upgrade was not done. I then reached out to MTN regarding the matter and I was told I owe MTN R1800 because my contract ended and I was now on a normal MTN data. I did not sign a contrcat that says i will be paying R1800 monthly for data now they disconnected my number because of that issue saying its my fault i did not upgrade, when I tell them to listen to the conversations between me and MTN they refuse and everytime we call they claim to have recorded the calls. I want them to listen to the call between me and their agent early march when i was upgrading online to show the fault is theirs not mine and I will not pay for something that they did. MTN IS A ****!