Faulty iphone 16 device

I am so disappointed at the bad service I am currently receiving from MTN. I took out a contract iphone from MTN N1 City. The device is an iphone16 and the phone was taken 2 months ago and the device is faulty. Its a new phone but only charges up to 60%. I went back to the store and they have taken it for repairs. Only when the phone was taken to Joburg and was alredy there i was told that the phone has a find my iphone tracker which must be removed before they can repair it. Why did the agents not tell me to switch the find my phone tracker before taking it to Joburg. Now they are saying they will send the phone back without fixing it and I must take it as is while i have to pay a contract for the next 3 years. The monthly amount is plus minus R1000. This is very unfair to me as a customer. I am extremely disappointed and frustrated. I refuse to pay for a faulty device and I will get my lawyers inlvolved!!