Gorman's Home Furnishing & Interior Design

Paid full price item delivered with defect
The sofa was delivered on august 2, when I bought was at the store but was brand new item , there were no defects or marks on it, I paid full price, only 10% discount given was because we paid right way, did not finance , when they delivered I notice a very big mark on the mattress, and I called right way, the solution was to send somebody to clean , the technician tried but could not clean, and he said that said they could not change the Matress because could damage the structure it's all wood, I called and they said they will send a especialize company to clean, but they said they cannot clean because was gel bed, so the company gormans offered me a refund of 650$ but I did not want , I want to exchange the sofa for a new one without defect, they said the only think they can do is repair the bed part , I don't want because of the structure gets compromised on the future, how
Do I complain , because it's not the company that made Fault