Bad Service

Good Morning,i have upgraded with mtn on 8th of august 2024 and received the phone the same day,all good the the next week tuesday the 12th august 2024 i needed to take a video for someone and realize the speaker sounds crackling so the day after the wednesday i took the phone back and they said they are going to send to mtn for evaluation since then i had to follow up the everyday and all they say they still waiting for approval they cant even just send me feedback on whats going on in the meantime i struggle without a phone,it already been more than a week that i have to wait everytime i ask them the n they said they would follow up and then nothing so then i have to ask them the next day again.i mean the phone was brand new i diidnt have it for 5 days.