Good morning friends I am really new to this thread... please I am using SL can I also use my sponsors health insurance for all areas where insurance is needed?

I got admission to study international physics at the leipzig university and I registered for the visa appointment on the same day 4th of July using a date in October as my start date but I haven’t got a date yet? I emailed the school and they said they can’t go beyond 18th October for enrollment... please any ideas? Thank you so much