FRUSTRATED EX NASHUA MOBILE CLIENT

I am one of the ex-Nashua Mobile clients sold off to MTN when Nashua closed it cellphone division. As part of my contract with Nashua Mobile (which appears to have been ceded to MTN) I received a Samsung Galaxy S4. The phone is not functioning properly and does not charge properly. To have the phone repaired under warranty I need a copy of my agreement and proof of purchase relating to the phone - I have requested a copy a long time ago but to date I have not received copies of the requested documents. MTN customer affairs continues to give me the run around and to date I have not received the necessary documents or any type of solution to the problem. When this contract runs out - off I go to the competition - after almost 20 years using MTN. Please help.<br>