How essential for us to receive official calls during weekend ? Do we have any matrix for such human behaviour? How managers are responsible for this?

In today's cut throat competition, a missed call can cost a lot; therefore, in my view point, in the given business environment, official calls should be attended duly in the off days too.

Well, as a matter of fact, such human behavior is of course not good ethically. But, this is a brutal world of business and ethics are mostly taught in business schools and practiced only where they don't hurt bottom line.

Managers are responsible if they do not deliver as per their commitments towards customers / bosses / fellow colleagues. On the other hand, if unrealistic demands on put on managers, they aren't the culprit.