Poor service and no attention to problem

This is the third complaint I publish on hellopeter. To date I have had absolutely no satisfying response to my problem. I am experiencing serious problems with my handset. My contract was originally with Nashua Mobile and then was transferred to MTN through the deal between MTN and Nashua mobile. The handset is giving me endless problems. It just switches off by itself and most of the times the person I speak to cannot hear me. I travel on my own early in the morning and late at night and do not feel safe at all as I never know if my phone will work or not. I sometimes am not even able to get into the complex where I live as I need my phone to open the gates. I feel that MTN is not paying adequate attention to my problem. I am told that the paperwork is with Nashua mobile and that they requested it. They have been requesting this for three months now. I am of the opinion that as long as I pay my monthly fees MTN is not interested in assisting me to solve my problem. I have been a loyal customer for quite a few years now and this is the way loyal customers are treated.