Most common tracking issues are described here, but in case of Post Affiliate Network there is one more thing that may interfere with tracking of clicks and sales.
It is essential to realize, that each account (merchant account) has separate ID that you may see at Accounts > Account manager.
Those accounts are independent of each other, therefore it is impossible to track a click, sale/lead if the affiliate banner/link (by which the customer is redirected to the merchant's e-commerce site) belongs to account with ID "XYZ" (so it is not the default network-owner account), but in the click and sale tracking code you are missing:
or you happen to have there
PostAffTracker.setAccountId('default1'); <== this refers to the network-owner account.
Each merchant has the proper click and sale/lead tracking code available inside their merchant panel at Tools > Integration