Disappointing customer service

I feel ******, I bought a phone last week Friday for my son, a 14 year old, realised Tuesday the 24th (Heritage day) when I tried to call him on the phone that I'm talking alone and he is not responsible, when I found out later in the day from him, he could hear everything that I was say as I could not hear him. I got a chance to test the phone last night myself, called my sister with it, she could not hear a thing and we were hearing her saying hallo hallo, phone came with a speaker or mic problem. I took it in today to only get an attitude from their superior and to be told I will not be getting a new phone, for a new phone with no fault, dent or what so ever. This is unacceptable, I feel ******. Ackermans Store 1918 Kwantu Centre, very poor service, don't wish to ever do any kind of shopping in that store ever again.