cant download music on my samsung sgh-s400i?

I cant seem to download music files on to my phone have tried different files and compessed files, from other phones and comp but nothing just says not aloud . I have enough memory but dont know if problem with the files i am trying to use or it is broke . I can download vids no probs my phone is samsung sgh-400i if anyone can help pls bofore i send it back thanks.