Terrible Service!!!

I app**** for a contract the 14th June 2021 - the consultant called me to advise that I was approved and then went on to confirm the contract for a fixed LTE router. I then received the device on the 18th June and once the courier left I opened and noticed that I was sent the incorrect device, I was sent a Mifi router instead of a Fixed LTE router. I returned the device the very same day sealed to MTN store as it was not what I required and called in to cancel the contract as I was in my 7 day grace period. I was told that the contract would be cancelled once the device reaches the Warehouse. I then went to MTN store to confirm if my contract was cancelled and they advised that only Mondo will be able to cancel it as they held it, and it showed on the computer that the device was returned to the Warehouse on the 25th June 2021. I called in again to cancel it and was advised that they couldn't pick up the device at the warehouse and that they would escalate my query, bare in mind my account was debited R748 on the first occasion and the second month it was deducted R1165 which was way more that what was agreed upon. To date I have had no feedback with regards to my contract cancellation and refund. I called the 25th Aug and a consultant advised me to send a bank statement to customer care for them to process the refund but to date I have had no confirmation of my cancelled contract or refund. I need urgent assistance.