My partner and my kids moved to Dortmund, then I later joined them early January. I was told I can't make Anmeldung in Rathaus, that i have to register myself in ausländerbehörde first because it's my first time in Dortmund. After registering my partner got a letter that we have to bring our arbeitsvertrag, lohnabrechnung, retenversicherung, krankenversicherung, and our kids ausweis. We asked them why they need these unterlagen, they said they have to prove my aufenhaltstitle again. That since I'm living in Dortmund, I need to have the document fron Dortmund. Not from the city i came from. I'm having 5years document, now I'm confused on what they want to do. Please I need an advice on what to do...