Nice to hear from you again.
The competent authority in this case is the Ausländerbehörde in the city/region that you are currently located at. They have to delete the Wonsitzauflage from your documents.
Can you tell us where you are living at the moment? The form might differ from Ausländerbehörde to Ausländerbehörde, so we can help you with the research if you tell us which one is responsible for you.