zumu llc took my merchandise and failed to pay Internet

sent zumu cd's back in May of 2013. They said I would be paid in 3 months. In August, I sent a email concerning payment. They wrote back saying my list didn't match what they had in merchandise and it was delaying payment. I asked that they send me back my cd's. They awnered that they could not, but that they had matched my list with theirs. And that payment was being processed. I wrote agian in November, and they assured me payment was on the way. Last month I wrote again asking them to return my cd's. I'm pretty sure I've been ripped off