It's my sixth day out of seven. I have the Interrail Pass for 30 days. Everything was alright till yesterday. Yesterday evening the train guards let me and my friend go but there was no ticket on their devices after they scanned our QR codes. They even told us that the ticket is "way too expired". The situation has repeated today. We are in Nordrhein-Westfalen in Germany. I can speak German only a little so we had to use the translator. It's stressful. I am worried and I don't know who I should contact and what I should do. Tomorrow we are going home, to Poland.