Welcome to the Wefugees Community and thank you for reaching out to us.
Before paying a lawyer, you and your father may want to contact a counselling office for support. Often they are experienced in getting in touch with the local immigration office or they can help you with writing reminders.
On this website you find a list of different organizations in Halle (Saale).
I hope this helps and and don't hesitate to get back to us with any further questions!
All the best,