unfair warranty practice

In 2010 I purchased a base set from Newholmes Furniyure in Pmburg for 6500 in total<br> We noticed this year that the mattress cover was fraying and the mattress became \lumpy"<br> They reported it to cloud nine who is their supplier<br> Cloud nine agreed that the mattress needed replacing however the catch is that they want me to pay a further 2808 for the use of the mattress<br> They based this on their current recommended retail value which is totally unfair since it should be based if at all on actual cost against actual usage<br> Most warranties are defined as the seller or producer replacing or repairing at no cost and they have a 25 year guarantee<br> I did make a fair offer (even though I don't think Im obliged to) of 2000 which was refused I think it is grossly unfair for me to have to pay this amount or any at all"""