Des En route Strand

I bought a ford fiesta car radio by this guy Des been wanting to buy it few months ago he said 1500 then I came back he said 1200 so I told him I'm gonna have trouble with my wife is there no better price so I took it he said it work he tested it fine after a hour I got the trouble from my wive I ask him can't I get a refund he said no refunds on Electricity parts so I put the radio in it doesn't work it's plug and play but no play I said I'm a customer of you guys and id never come back again how can I do this can I involve small claims court or do I have no case