Shockingly BAD service

I was due an upgrade on MTN, and was called about it and went ahead , received an IPhone 16 which then froze on hello screen. The only way to get a new phone was then to send away the phone for “repairs” or cancel the upgrade and get the phone collected , the phone was collected on 17th December 2024, but the upgrade has not been cancelled and I cannot continue with another upgrade until it is done. I am now told this can take between 21-30 days which was not communicated.