What is the ruling on the Hajj of one who threw the Jamarat and doubted whether some of the pebbles fell into the basin, and was certain that he had forgotten to throw a pebble on behalf of his female client, and doubted the number of pebbles he threw on the last day after re-throwing one of the Jamarat?

Doubt after completing an act of worship has no effect. As for throwing the pebbles, the majority of scholars are of the opinion that whoever throws only six pebbles, their throwing is not considered valid, and they must offer a sacrifice (dam) to be slaughtered in Mecca and distributed among the poor of the Haram. She (the one for whom the pebbles were thrown, if applicable) can claim back the value of the blood from the thrower because he caused the deficiency. However, Imam Ahmad holds that there is no harm in omitting one or two pebbles, and that this does not cause any detriment.