Extremely bad service via Facebook and Call Centre

I have been in contact with Telkom via Facebook Messenger and with their call centre agents.I was charged for a contract that has expired, when I queried this, I was advised that I received 5G data. When I switch my router on it says "out of airtime". I was also told at what times I was using the data, I advised the call centre that it's not correct as it shows "out of airtime". I've asked to be refunded or to be given this 5G data then as someone else is definitely using this data that only Telkom can see. I've asked to cancel this contract. I was given a link, I followed all the prompts, once completed it says that you will receive and sms/email or be contacted, nothing. I did it again and same message and still have not received an sms/email or call with the case number. Your call centre cannot cancel the contract without the case number. Please provide the case number. The service I have been getting from Telkom is extremely disappointing. I was asked to provide my address, I did and still have not had any feedback on this so called 5G data which I am supposedly using.