how do i use the ringtunes i've downloaded to my phone? i'm assuming they have to be locked, so how do i do this?

Coz ur phone is branded!!!!! Debrand it!

How do I debrand my phone? Can you send me a link that I can read to follow instructions? Oh and thank you very much for your reply.

DRM packager with MP trim should do the trick
Its a cheat, you can't use full songs, but you can create your own "clip" that your phone will play as ringtone or message alert