Worn out couch

Good day December 2017 i took up a combo with Rochester in Centurion .Up to date i have not received good services.i sent them an email within 7 days after they delivered my goods that im not happy with the the way the couch is..the couch iv been given is hard on the other ends and soft on other ends,after getting up from the couch it will still be shaped with your buttocks...i have numerous emails communicating with theses guys since then coz i feel its unfair for me to be paying for such...i went to the store,spoke to Richard the manager and he said they have received numerous complaints about the couch and he said they are gonna change the couch completely assuring me that it will be deliverd to me differently and in a good condition.Couch was only delivered in May this year and nothing had changed,i immediately phoned Richard he told me he will enquire as its late and the ware house has closed..few days after i received an email from Richard with a forwarded message that had sketches saying that that couch is made like that and its supposed to be hard and soft on other sides.Richard **** to me saying the couch will be changed completely with good condition,i complained about couch within 7 days and nothing was done...the combo had a table of which i was supposed to get a white table but they have been sending me the same colour and till today i still have not received a white table.Had asked Richard to speak to his manager about giving me different couch and il top up if there is a price difference and he said its impossible coz of the contract...my concern is il be paying for a couch that wont be in good condition in the long run coz the quality is very bad.I honestly dont know what to do coz iv been paying them accordingly and have never missed a payment.Please assist on way forward coz that couch is an embarassment.