Looks like Sana's alleged chest bump didn't go well with her haters. They raised serious concerns over it, took digs at her character, gave funny (in their head) justifications and what not.
First of all it was a SHOULDER BUMP as Salman mentioned and NOT a CHEST BUMP. Her haters need to remove hate lenses off their eyes to see the true picture.
It all started with Dey taking clay off Sana's ladder and placing it on Mahira's, that's when Sana went after him saying there he can have more clay. May be it was her strategy to irritate Dey so he does not repeat it.
In this GIF you can clearly see Dey violently pushes Sana before she starts SHOULDER bumping him. She perhaps thought using her shoulder she won't break the rules and who needs hands to displace a mosquito anyways.