Not "prove". "Confirm". If you ask somebody to do something, they might do it, or they might not, whether out of passive malice or carelessness. Saying you have

Not "prove". "Confirm". If you ask somebody to do something, they might do it, or they might not, whether out of passive malice or carelessness. Saying you have done something which you haven't done requires active malice, which is much less common.