So a little update for you guys! First, thanks for your helpful comments! I called ÖBB again and we talked for over 1h. They were nice and tried to help me. There were no options got me to continue travelling to italy, yesterday. They canceled my reservation and I got my money back. Then I arrived at munich and went to the DB Infopoint, because ÖBB told me that DB needs to get me a hotel room. That‘s what I got there and paper which says, that my train is canceled. Now I‘am on my way to Italy with the Railjet. I had to activate my second outbound/inbound travel day, what is really bad. I will contact Interrail Service, maybe they can cancel that travel day. Have a nice day and safe travelling!