Damaged couches

On about March 2018 I purchased the couches at house and home, on august 2018 I felt the sagging on the couches and I reported them and they came and collected them, since august they have been keeping my couches with them and when I asked the how far they are, first they told me they were not booked for repair and they don't know why but they will make sure they book them, during September I made enquiry wit the salesperson and she told me the couches are back but they still sagging, so I waited again for them to be fixed, last week I received an email that I must go to the shop and collect the couches as they are fixed and when I got there they still the same and the salesperson Shaun agreed with me, now they telling me they have to send them for repairs again, this is been long overdue and according to their rules, if the customer doesn't get their product in 7 days they need to refund the customer but in this case they refusing. I ended up purchasing the couches because its hard to sit on the floor. Please assist me to get my refund

Thank you