Mattress Kings

I bought 2 mattresses tempur pedic from them and the policy i could exchange the mattresses if is the same no extra pay but if different one i will pay the difference , after 45 days trying to exchange the soft with the hard one they want a $3000 difference ,my mistake i didn't let them put that in writing, very bad thiefs don't buy nothing from them, and before you leave you must write a great review for them while you are there or they will refuse the delivery, they are thieves 100%, the price is the same price and same one exactly just im trying to get the hard one because the the one I have is the soft one