Telkom Services are poor!!!

During the lock down in 2020 most of the people worked from home and therefore we needed data to do so. I saw a reasonable deal for a data sim with telkom and contacted them. The consultant was very professional and did a network area check. According to them the sim was able to connect to a network in my area. Upon receiving the sim I learned it was not connecting at all. I contacted the helpline but no assistance was given. In other words I have been paying for services for months without the desired service I signed up for. Later on I stopped the debit order and than started receiving demanding calls and sms's. All the agents I spoke to could not help me. I ended up paying the outstanding balance wich accumulated to R2395 and requested the agent to cancel the agreement... Almost 2 years later I started receiving weird sms"s from HP attorneys demanding payment. I called them and they told me I owe Telkom an amount of R551. Of course I refused to pay without proper investigation so I called Telkom and they told me the R129 accumulated to a further R551 after I requested the contract to be canceled. Now understand this: I paid over R2500 already for data I never utilized and now they want a further R551? Please help me understand how this is fair!!! I am furious! What happened to TCF (treating customers fairly). The next thing they blacklist your name over a mistake from their side. This needs to STOP!!! Consumers are battling already and the service providers don't make it any easier on us...