Bad service Ackermans Graaff Reinet

The black friday 23 November, I purchased a cellphone from newly opened Ackermans Graaff Reinet. When I selected the phone I noticed it wasnt sealed in plastic cover, they assured me its was brand new. On Thuesday 4 days there afterthe phone started to give problems and cut of calls and also switch itself off. I recently started my own bussiness and that is one of the reasons I bought the phone. Due to my heavy workload I couldnt return it to the store during the week. On Saturday 1 December I returned it and the service was very bad. They didnt even listern to my query and assumed it was my fault, also I was explained the 7 day return policy. They dont want to exchange the phone the reason being might be that the store manager are new (new store opened last month), proper training wasnt given, staff not accurate with open and seal cellphone boxes, and customer service is a big issue. Would really like some feedback from superiors regarding my complaint. Im currently unavailible due the phone issue but please use my wifes number **********