Incredible worst service ever

I bought a R2800 bluetooth speaker at incredible and went back for a refund cause i hated the speaker. I ended up buying a R2000 speaker and they put the other R800 in a gift card at the end of last year. Last week I went there to use the gift card and they told me there is nothing on the gift card which means they probably made a mistake last year and now they said they can't help me.