Electric Pot defective

I have sent my electric AMC cooker in for repairs three times this year and each time the pot is returned saying it has been repaired or nothing is wrong with it. i am really fed up now and have told the agent to rather keep the pot as it is of no benefit to me and i would rather not be treated like a fool when the pot is clearly faulty. i am told that i do not know how to use the pot which is a load of *******. pot only goes on high heat, does not boil and on low heat will go on for 3 hours and nothing gets cooked. its disgusting that the after service of AMC will not bother to even acknowledge a defective pot and would rather pass the buck that i do not know how to use a pot.. replace the pot or refund my money.. I am done with AMC