Fed up with damaged goods

I am fed up with Lewis stores. We bought couches at Lewis about a year ago. After 3 months 2 of the 3 couches broke. It took us a further 3 months for their people to come out and fix the couches. After a week the couch that was fixed broke again. Then tonight we were sitting on the couch and the other couch broke. How the hell to they expect us to pay for goods which seems to be assembled by 3year olds? we do not have children and we only sit on them so how can they break? We aren't even overweight.. Do not even try to speak to someone from head office as they are also ***********. SO here is the situation... I demand new couches and we will not pay for it. How can you expect to sell couches for R7000 when it only lasts 1 year. Please phone me someone from head office so we can sort this out. I am NEVER buying ANYTHING from you as you only sell damaged goods!! sorry you lost me..