Horrible customer service

I bought a cellphone for my mum and when I went home not even an hour later she wanted to have a cellphone that has whatsapp on. I went back to the store and was told I can exchange the device even though I'm willing to pay more and the device was not used. I called customer service an was told if I did not sign the terms and Conditions the exchange needs to be done. I did not sign anythibg however the area manager Pierre Peters does not want this to be done so much for customer service. I'm at home with a new born and Pierre is making my life so hard I'm giving more money to your damn store what kind of area manager is this.i just want to add a R300 and get my mom a better cellphone at you store. How hard is this. When we went in yesterday he was not answering his phone.

I want to be called back from Pierre.

I want this sorted as soon as possible.