Stinking bad service

Having purchased a bed for R86 000 which is still under guarantee and has a major problem with the mattress which is sinking their after sales service stinks. I have sent them photographs of the mattress which unfortunately does not show very clearly what the problem is. After numerous phone calls they are refusing to send one of their specialists to exam the mattress and sort out the problem. They have one excuse after the other as to why the mattress should be sinking but refuse to take responsibility.