Argos Sofa Rights on Refund not replacement

Hi All, We have bought a sofa from Argos and had it replaced due to bad quality, the replacement has also been attended to and is also of inferior quality as stated by the expert "Leatherman", we have asked Argos for a refund but they say they are entitled to only offer a replacement, my question is can we refuse on the grounds of having 3 call outs and having already tried a replacement, my wife (and I have lost confidence in the product)

Thanks New User Doug