They wont give me a full refund of money i sent to them in error

I am so sick of being bul**** by Vox telecom!!! I took out a contract with them around June or July 2019 when I moved into my previous apartment, in Dec of that year I had to move abruptly due to personal reasons and was still renting out the unit in dec even though I had left by the end of Nov.

I had notified the sales agent that was assisting me to cancel the contract. He confimred that he logged the cancellation and that someone would be in touch to collect the device. To this day no one has been contacted me. I kept on responding to their emails to request someone to contact me regarding the devive and no one responses to any of my attempts ( i have emails and WhatsApp messages as proof).

the weekend of the 29/05/21 I accidentally paid R 9000 into their account as it is a public account the receipt is saved as "my name" hence the confusion when paying. I have been informed that I owe them money from the time I left as they received a cancellation in dec? how is that possible when the guy who was assisting me confirmed that it was logged. secondly, they are charging me for the device that due to their poor administration they failed to collect even after numerous requests( it even states on the contract that they will collect and deliver) now i was told that I need to courier the device? How?

They refuse to release my rent money. someone anyone please help. i have had it with being bul**** by this company. this is week and I still have not been reimbursed and I have not been able to pay my rent They want to send back R 3700 from the R 9000? are they insane how am I supposed to pay rent. I have 2 kids. do they really expect me to be thrown out? I will be further referring the matter to small claims court, I am sure I am not the only one who has gone through this.