Sagging couches plus stinking attitude

I bought couches last year to a rude salesperson called Piet at Sedgars Eastrand mall (well nice until sale was concluded). Let me just say I was happy to part ways with Sedgars but not even a year after buying the couches have sagged. I've sent emails to the email that is provided 2 weeks ago but with no respond. I personally went to the store to enquire about the non response (to my surprise I was told the email address doesn't exist, despite being in all their invoices). Well I spoke to Prudence at first, who called Piet to come assist as the sale was concluded by him (the rude man didn't even bother to come, he just walked away). Prudence took my details & promised to lodge a complaint to their complaints department, so that they can assist. To date haven't heard anything from sedgars & I'm sitting on these expensive sinking couches. The 2nd issue would be for Sedgars to take some of their employees like Piet, to a customer service course. I am really unhappy about the quality of product I got (paid cash) & the customer service. Can Sedgars please bring me products that are worthy for the money I paid