The -+R7600 matress is hurting my wife and my back

We have bought a brand new mattress only from the Bed Shop in Trichardt in February 2015. The next week we were experiencing severe back problems that we cannot bare the pain. So I turned the mattress to see if it was the bed. So the extended length of the bed was not used as it was supposed because we both are very tall. And the bedding was not fitting our legs was out of the bed and no blankets covering our legs. After a week I have found out that it was the bed. I tested the bed by sitting on the bed all over the edges. I found out that the bed has a piece of wood running across the bed which is on our lower backs/spine which caused the back pains. Currently we have the mattress upside down. Meaning the bottom part of the mattress that must face the base we are sleeping on it and the soft part that TELLS US THIS IS THE CORRECT SIDE is facing the base. I have went to the shop after a week of the purchase of the mattress. they told me that they will send someone from their shop. Up to now nobody came. So I went to them three other times. I went to them on the 26 June 2015 again. This time the owner became nasty and had a bad attitude with. Up to now nobody came home.