Rock hard bed and bad customer service

We have recently bought a bed on 29 March 2018, which was delivered on 18 April 2018, the make of the bed is sleepworld. We have called into your offices regarding the fact that the bed is unsuitable, it is hard, uncomfortable and has caused us immense pain. We spoke to Asanda and the store manager. The lady we spoke to has said that she is unable to exchange the bed despite my complaints and despite the fact that we had only used the bed for one day, at which point it was realized that the bed in not what it was sold to be. They have failed to provide adequate reasons as to why the bed cannot be exchanged. We have read through the terms and conditions of the warranty provided, you will note that it has no requirement that the plastic must be kept on, in order for the bed to be returned or exchanged. We request that you please provide us with an exchange or a refund, as the bed has caused injury and lack of support due to the hardness, failing which we will have to appeal to the Consumer Protection Act for recourse.