Complain - House and home

I bought a bed in Sept 2017 from House & Home N1 City on higher purchase (2 years). I paid off the bed within 3 months. Beginning of Sept 2018 I noticed the springs on the side of the bed is pushing out and also the centre of the bed is making a loop, something that the sales person at the time we bought the bed said will not happen.I went to the store and indicate this to the sales person, who indicated they will log a call with the service provider and get back to me. Since the 3rd September I have visited the store, spoken to the Divisional manger, store manager, etc about the problem. They all promise to get back to me on the issue without doing so. I keep on visiting the store, speaking to them and getting empty promises. On the 27th September I received a call from the sales person, Maryke who informed they are having problems with Serta as they need to resolve matter, but promised it will be resolved. The same day the manager, John called me to give me his assurance he is on top of things and it will be sorted, which to day has not been resolved. In the meantime I am sleeping very uncomfortable and not getting a response from the store.