Lets assume X drives a taxi. A, B and C sign a contract with X such that they use his taxi service to commute to their office everyday in exchange of a fixed money as fees; say 1000 rupees per month. Now A pays the fees every month while B and C have to be reminded of it. B pays once he gets reminded while C neglects it. X says he will not be able to continue serving C until he pays the fees. C never cares. X decides to leave him off and only pick A and B next time. As a result, C could not show up at his office.
Now, should the company that has hired C blame him for his irresponsible attitude or X for not providing his service to C though the terms in the agreed contract were not met?
As per some members here, X should continue serving him despite C not abiding to contract.