Telkom LTE is the worst internet i have ever had!!

I have had Telkom LTE 100GB for 15 days now and in that time I had very slow speed and the thing keep on dropping my internet connection. I want to cancel this as I have not received what was promised and contracted but now they are talking about a penalty. Why should I pay a penalty if the service is not what they promised??!!?? Telkom is the worst wireless ISP that I have ever had the displeasure of using. You call the call centre and is on hold for an hour and they don't seem to want to help. Just sitting on hold has cost me a fortune!!! I want this contract canceled due to bad service!!