MTN Poor service

On 01.09.2022 i took a contract a Samsung A73 with order number *** and was assisted by Menzi Paul Ndaba. On day of delivery i was not happy with a phone and i took it to my nearest mtn store for return and i was given IRMS 918217 with ***. I called Mondo cancellation department several times and i gave them the IRMS number to cancel i even logged multiple SR with mtn for Mondo to contact me should they need further information but up to this day which is 02.12.2022 the contract has not been canceled and i have been billed every month. This contract has affected my credit score. Poor poor service because when i go to mtn store i can not be assisted because i took the contract online and when i contact Mondo they do not assist me to resolve this matter