Bad Service MTN / Samsung

I signed up for a contract with MTN for a Samsung Galaxy Prime, They did not have stock at the shop where I signed the contract, so we had to go to a different shop to collect the phone. I was given the phone at Springs Mall, they opened the box but did not test the device. So when I got home and started setting up the phone, when the memory card was inserted it did not read the card so we tried 3 different micro sd cards, none worked. so the next day we returned the phone to Springs MTN, they then explained that the phone is faulty and needs to be swapped, but this could only be done at the shop where I signed the contract, So driving from Springs To Carnival Mall. When I got there they said they cant just replace the phone as we had damaged the slot. then after an argument they said it needs to be sent to a technician to make the decision whether it can be replaced or not. to add to my frustration the device has been at the shop from the 7th and have yet to be sent away!!! and now they say it will take up to 4 to 5 weeks before any decision can be made. This would mean I would have paid my first installment already without having the use of the device, before receiving an answer whether its a factory fault or not. When we wanted to cancel the contract we were told we can't, please remember under the new credit act you have a 7 day cool off period. I would like to receive a new device or the contract to be canceled.