Need my Five & half grand back,.

Bad, very bad i bought a press machine last year August, till now i haven't received anything and this month when asking for my refund i am told that the account is closed but i didn't get any of my money they're not even sending me a proof of refund to see which account did they use because i've been in contact with Nedbank and nothing has been paid bak to my Credi card account,. and i can't even get any help from their online chat as i'm always told to contact my seller but they don't provide any sort of contacts - because i bought from them ,.