AAT and FCC Related Inquiry after student visa Refusal

AAT -

What is the maximum time - frame of AAT’s decision after hearing? Mine has already been a month.

What could be the possible of reason of time delay in decision? In what time- frame generally the decision comes?

FCC -

Should someone only go to the FCC, if there is jurisdictional error in the decision? Otherwise, what could be consequences, if one would like to go anyway? In current scenario, how long does it take for the first hearing to come e.g. Sydney?

Pls Advise