Bad Service

Bought a bed in the store in 08 February 2019. I requested a back support bed and a Sealy Bailey was recommended. I paid cash and for delivery as well. I slept on the mattress for the first two weeks and I experienced a serious hardness of the mattress. I brought it to the store's attention and I was told to turn the mattress around to try other sides and told them that I sleep alone on the bed and slept on all sides of the mattress and the hardness is all over the bed. I was told that they have a policy of 120 sleep which is 3 months and that had passed and I still have a hard mattress that hurts my back instead of support. I went to the shop on numerous occasions now to request assistance and every time I'm told the matter has been escalated and they will come and assess the mattress. Today is the 2nd of August 2019 and still no help from the store and I am really frustrated.The store at first blamed it on the manufacturer who is Sealy Posturepedic. The manufacturer was contacted and they have confirmed that indeed the mattress is a hard mattress and not a back support therefore it is not a technical fault as the store imp****. The manufacturer also confirmed that an exchange is possible however it must come from the store as they are the ones sold a wrong product to the client. I have told the store that I do not want a refund but a an exchange even if I have to pay more if the mattress I'm looking for could cost more. I just need the store to exchange the bed for me.Thank you