unlocking a micro scandisk memory card?

i have a micro scan disk mem card in my cell phone. Unfortunitly i've had to change phones a couple times and every time i do, it locks all of my music and ringtones on the card!!!
the people at the cell phone place refuse to unlock it even though i'm pretty sure they know how!
i mean they sell you the cards to add memory to your phone and then they refuse to unlock it so that you can use it!?!?!?
im frustrated and i know theres people out there that know how to do this!! any help??
~K