Mtn contract

I have a problem with MTN , I have upgraded my contact with them ... I requested for an iPhone 7plus and I was given a I phone 7. I called the call center to assist me to change it. I took it to the nearest MTN Store (Hillcrest) I was told that I will receive an SMS with a tracking number that was on Friday 22/11/2019 till today I have not received it. I called today and they keep giving me different numbers to call but no one is assisting me I asked if I could speak to a supervisor from the number I was given they keep saying it the wrong department. I am so annoyed with MTN right now. I keep on going from one call to another, they are giving me same number and they say it is the wrong department and still want to give me the number I got on the first place... please help me