Our system sends INSTANT notification messages (via e-mail). If you received 2 notification messages in a row, it probably means that 2 affiliate sales were made nearly simultaneously. Then everything is fine and your promotion is highly effective!
However, there is another possible case. Occasionally customers reload the web-page several times. Then our system will treat it as several sales, and will send you duplicated notification messages.
At the end of a month we will check your affiliate sales and remove duplicated ones. In the meantime, however, you can see an incorrect statistics in your affiliate account. We are sorry for that.