Worst customer service

Hi I took a contract with MTN Mondo in August and received the iPhone13 within 3days it stopped working returned it on the fourth day and cancelled contract since then I have been calling and going to MTN nobody cares they will transfer your call until you get fed up a manger promised to call me I have never received the call ,sent emails even a complaint email nobody responded no body cares they took money and have been trying to take more money but they have the phone this has affected my credit score till today they have not cancelled...I have received the most appalling service I would not recommend MTN to anybody they just don't care