NO desire to help

I would like to share my total disgust with MTN regarding my recent experience with them at a shop in Kollonade Pretoria. With my phone still under warranty, I took it back as it is faulty. It got sent in and came back 3 weeks later with the result that the phone cannot be replaced because there is deep scratches on the cover and the data cable is faulty. So I let the salesman inspect the phone and show me these scratches and test the cable...he could not find any problem and said sorry he can't help me further. So I took the Phone to Samsung Mobile South Africa . I showed them the comments from MTN and ask them to point out those scratches and also test the data cable....the Samsung representative could not find ANY physical damage to the phone or cable as stated by MTN and advised that they should have replaced the phone. What am I to do now MTN???