Someone using my music on CDs w/o my permission

Florida - what should I do? Thanks in advance.

With so little details, the only advice we can give is to consult with an entertainment attorney in your area.

Too few details. Do you mean your composition or your performance?
Had you released the song yourself? In the US, PERMISSION is not necessary to issue covers of previously released songs. Royalties (at a statutory rate) have to be paid, but the license is compulsory.