You know, I was shocked when I saw that some asshole is threating you with a lawsuit. But there is a legal way to end this. How, you ask? Simple - rent a serwer in China or other place, where lawsuits can wipe their asses with their demands.
There is a simple rule - contents on the serwer are only valid, where the location of the server valids them. There are different laws all over the world. Find one country, that doesn't ban mp3s and put the server there. Simple - yes, you only have to look. Expensive - that only depends what you'll find.