Official Acceptance Letter

Hello everyone! I am a non-EU student trying to reach for the winter semester. I need the official Acceptance letter for my visa application. However, it has already been 2 weeks since all my documents have been fully submitted. My visa appointment is pretty soon, how long does it take to issue the Acceptance letter? And is there is anything I can do to accelerate this process and get an Acceptance letter soon? Can I contact someone who can help me?

A lot of people are also on holiday so I'm confused about how I can reach out to as well. Any guidance would be welcome...

Thank you.