How are opposition proceedings carried out?
After raising written opposition, you will be informed that the authorities have received your opposition. If the authorities do not change their opinion, a second authority is going to review your opposition. This authority may invite you to discuss the case together. You are not obliged to appear personally but it could certainly help to explain your situation in detail.
As soon as the authority has come to a conclusion, you will be informed about the decision and the reasons. If you receive a negative decision, you can now file a lawsuit against it.