Why is my student visa taking so long

I applied for a student visa on 3rd august (gave my documents to tls tunis).i have a mandatory placement test on 28th September in jena university for dsh vorbereitung kurs.I also hold a conditional admission for applied computer science masters at another university.i contact the auslandbehorde in jena and they said my application didn't reach them.for anyone who applied is it normal that after almost 6 weeks i got no reply ?and what can i do to not miss the test ,the university confirmed they won't delay it or accept late arrival they told me i need to reapply for the next semester