Salary Issue

I have a left the company because of misbehaviour of manager with immediate effect without giving any prior notice of 1 month as mentioned by them in offer letter but they never provided me ,Appointment or joining letter so i cleared them on email that notice period only valid when employee & employer signed any agreement & i mentioned a date on resignation that i want to my pending salary to be credited by that date only but they didn't provided . Along with me there are 10 more employees whose salary is pending from 6-7 months & few employees they haven't gave any resignation because company told them to left because it was sales office so they forced them to left in between their tenure ,Now we are all together & thinking to go to labour court so please advise it will be good decision in favour of us or will it harm us because many employees didn't even get the offer letters & company also deducted 50% salary every month when we fail to achieve the assigned targets ,they mentioned everything on offer letter but we never sent agreed email to them . Kindly please advise what we can do to get all our pending Salaries