And you are incapable of sending

A: You should pay this worker the sum you promised him to keep on digging for the pipes in order to fulfill your promise, for violating the promise is one of the attributes of hypocrites, and surely you would not like to be described as a hypocrite. Thus, if he does not come back and you do not know him, give it away in charity on his behalf. If he returns, tell him what you have done, if he forgives you and accepts, then there is no problem. If he does not accept, then you should pay him his money, and in this case the reward for charity will be yours. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions