Very angry and dissatisfied customer!

Worst customer service ever! I had a 2 year wifi contract with Cell C. I had to discontinue my contract due to no work no no pay because of Covid-19. I phoned 28 July to discontinue the contract and was advised that it was to early and that I needed to phone back any day in August. I specifically asked them if they are sure because I do not want to be penalized anything extra. I was assured that this would not happen. Phoned on the 12 of Aug to discontinue my contract. Did not receive any proof that this was done and phoned again 31 Aug to get proof. 7 Sep I got my statement and R402,00 was added extra onto my bill. I phoned the billing department (08 Sep) and spoke to Kamo who advised me that this was a post payment and it will be credited back to me. No such thing happened and I have not been able to get a hold of Kamo eversince. I have been phoning non stop since 30 Sep to get answers but nobody can give me a direct answer. I only get reference numbers no with feedback. I spoke to a supervisor, Tina, on 20 Oct who promised me she will phone me back before 17H00 that day, still no phone call. Phoned her back 22 Oct, she was not in the office but she was send an email to contact me. Phoned again 23 Oct, spoke to Leratto who gave me another ref number and said someone will contact me in 48 working hours. Still no feedback from this as well. My money has not been paid back. Nobody is calling me back, they just say it is ongoing and they will contact me. Spoke to supervisor Tabalo this morning who was also unable to assist me, he put me through to a number where I had to listen to music for half an hour without any help. This is the worst experience I ever had. They are quick to take my money but when you want yours back they ignore you. I am very disappointed with this service. I work in customer service and making a promise to a customer and not following up is not something you do.