Follow-up on the Repairs complain

This is a follow-up Query since there is no response on repairs, On the 14/01/2015 i logged a complain on the Repairs of a cellphone SonyZ1 booked on 28/11/2014. I spoke to a lady (Veronica) on the 23/01/2015 who said she will ensure response on my query REQ:***. To date i have not received a repaired cellphone nor my cellphone back from MTN repair centre, i called their number ***) never getting to speak to any1. I am continuing to pay monthly installment of a product i dont have this is ridiculous and rip-off. I cannot pay for a cellphone that is still under warranty and guarantee and i am not responsible for water damage since i dd not put it inside water and i am told those are the diagnosis and in any case the features of that handset states that its water proof/resistance now am falsely accused of negligence this is always their diagnosis not first time and its not acceptable. The IMEI number is ***. Now i still say since they are running away from giving me my handset means they are guilty on diagnosis. The fact that i am accused here of wrong doing it does not sit well with me and that i must pay to get that handset back. I want my handset SonyZ1.