Oh boy can I relate and don't I have a horror story from my last trip! After the festival when I got to Itzehoe, I realised my phone was missing. I got someone to call it and a kind person had found it and handed it in at the Wacken box office, so back on the next bus I went (including one group of entitled bike riders who held us up and wouldn't get off the road for 5 seconds to let the driver pass, until the bus driver pulled up beside them and told them off - I assume; my German isn't that good, which according to them made him the arsehole somehow). Checked all the dixies at the Wacken entrance and they were all 100% unusable. Picked up my phone and got on the next bus back. The train station WC was out of order. One ticket machine was broken an no one works on Sundays, so the line was down the stairs and onto the platform long to get a ticket. By the time I got one, I had 10 minutes to spare before the last possible train that would get me to the airport in time for my flight. By then I was so stressed, hungry and dehydrated that I nearly fainted. WC on the train wasn't working either, fml. Literally had to wait until Hamburg airport; would not recommend.
Moral of the story: don't lose your belongings and get your train ticket back in advance. The 9 Euro ticket looks like an amazing idea.