Pep Refusing to Accept Faulty Phone

I bought a Mobicel Berry at Pep Store 0238 Potchefstroom. It is a dual sim phone that comes with a Telkom sim. I overheard 2 store assistants speaking about "sim block" if you try to use another sim card other than the one the phone came with and I asked the cashier who helped me if that applies to this phone because I already had 2 MTN sim cards I intended to use for the phone. She told me it did not matter even if I threw away the Telkom sim because the phone would accept any sim card. She then took the phone out of the box, put in the Telkom sim and "registered" it on the phone. When I got home and tried to use my 2 sims, one of them was not working. I use my 2nd sim for data, and the phone constantly says I don't have an internet connection.

The store is now refusing to refund my purchase. The manager Constance was VERY rude and started screaming at me the moment she heard my complaint this morning. She said she knew from the moment she saw me that I would be a problem - I was asking about technicalities of the phone, sim card use, etc and she said I have a problem. Is it not normal to ask such questions when buying an electronic device?

When I tried to explain my issue Constance would constantly talk over me and tell me that I just want to cause trouble. She is not open to customer enquiries, doesn't greet customers. When I went to try to get a refund/exchange, she said she called someone and they told her I can't be helped. I asked her to call whoever she called in my presence and she took some till roll paper, wrote the number down and told me to call them myself. She never apologised for any inconvenience.

I am very disappointed in how I was treated like a ****, and when I asked relevant questions the responses were "don't worry".

Please help.