DEFY Stove Top Malfunctioning

Good day, I bought a Defy Oven and Stove top set 3 months ago. We do not use it often but when we use the stove the plate gets so hot it actually warps the stove top while it is on. Then when you switch the switch to turn it off it trips the electricity. The sliver top is no longer silver due to this. It is now going bronze. I am bought the stove as I am selling my house and I am sure this model is a manufacturing problem.

Model Number is DHD399 DCB013-DEFY COMBO DBO461 & DHD399