I don't think zoya is being fake...thats how it was written...zoya is scared to fall in love and that is why she is using this reason to stay away from adi...adi did do the prank call...and zoya is upset because of that...and right after adi confessed his love...so thats alot for zoya to take in...add in the fact that she was betrayed badly by yash...the girl has every right to want to stay away from any kind of love...
as for arshad's character...i think he is signed on for 1 month and i don't thats been complete yet...unless his character turns negative and he has reason to stay...i think his role will end once zoya admits her love for adi during this marriage preparation track.