Little story

Hi all,



I have a little story and a fast question for all:



Me and my friend, same clan and both have main 99 , tank, and start a new dual, we choose same dual class: iss.



I leave clan due internal disagreements ... after a month or so I have seen my old friend in dual and ...... he is 99 .... but i don't understand how he can be 99 after 1 month while my dual is 89 ....



Question: How i can do lvl 85 to 99 in 1 month or so?



Thanks all