Furniture and money gone

My mom purchased sofas cash worth 20 k January 2017 from the benoni branch ,we later realized that they were uncomfortable and felt like they were going to collapse ,we contacted them and reported them and after much run around they came and collected a piece from the set ,we then again the following year in 2018 late,reported that the same sofa had collapsed and the others were just looking flat and we wanted new ones ,they advised that they would come back as its festive season ,only late 2019 they came to collect the the other set but left the others (bearing in mind that a million calls were made to the branch) they collected and to date they haven't brought them back..branch manager advised that the matter was with their warehouse manager...again today as usual we followed up and we told that they out of the two year warranty and we have to pay 750 for them to return. I believe we've been co operating well and given them grace to sort the matter out.They said the fee was for the springs they put just like the other ones but I told them that they all not ohk,asked them to come fetch them and give us new ones or our money back,im very saddened by the whole ordeal ,we have so much on phone calls and going to branches with no assistance...where does one go from here,they gave us a substandard product and even though they are aware that it had factory fault by no means did they try assist,worse we don't even have the sofa anymore they have it and the money