Did you receive Appointment Letter from the Company B? If the company has not been issued or even if they have issued but you have not acknowledged it then employer-employee relationship is not established. Above all, it is not even a question of receipt of Appointment Letter. You must join on specified day. Once you join then only formal relationship will get established. Sans this relationship, any activity that Company B does is unenforceable.
It appears that Company B has jumped the gun. Anyway that is their internal matter. By the way, what exactly is e-code? Do you mean to say that they have allotted you the Employee No to you in their HRIS/HRMS? In that case, they counted their chickens before they're hatched. Nothing is as jerky as this!
27th November 2016 From India, Bangalore