I'm promoting the same offer on the same website with the same ad but with two diffrent networkds. When my cj.com ad is live my sales drop. Do they track a sale to completion or does the advertiser track the sale and send cj the "sold" command?

There are different methods for tracking.

Most commonly the sale pixel will be hosted on the confirmation page of the merchan, which will fire when a sale has been completed. In this instance it will be visible within your CJ tracking within approximately 2 hours.

For this method reversals may still be put through if the sale is cancelled.

The other method is for the merchant to batch in the sales driven from the affiliates at a later date. A lot of the gambling merchants do this.

It is also worth noting that not all merchants match up the CJ sales and order id's to their own order id's, therefore meaning reversals and cancellations are never fed back into the tracking.