We have had customers reporting that it took up to 12 hours after they made payment before receiving the email acknowledgement. There is no fixed time period but under normal circumstances you should get your email literally within a few minutes. However, due to heavy traffic this can extend to several hours. And if there are glitches on the mail server, sometimes the email does not get delivered at all but this is very rare. In any case, if you did not receive anything after 12 hrs then please contact Customer Support Services immediately and they will trace your order and resolve your problem speedily.