Nikon denies do repair my camera

Nikon (Premium Brand) denies to repair my D5100 because it has been tampered (I bough it second hand). They must offer some warranty on their repairing services, and they cannot give me so since my camera has been tampered. I can understand, but another solution must be provided. Since here in Cape Town all the other shops sends the cameras to Nikon, I cannot have it repaired at all. If I send it to any other shop, they are going to analyse it, send it to Nikon, who will deny the service. I'm stuck with this camera!