chefslot:
Yes it did, it said card removed when no card was present, then when card was added it Serial.printed the uid.
So then moving on i added all the other mp3 parts
Let's move forward in baby-steps. The way you have added stuff has screwed things up.
In my suggested code you will note that I left the fadeOutMP3() function empty. Just add a simple message into it and see what happens - perhaps Serial.println("In fadeOut function");
...R