Each time a user attempts to purchase points, their request is saved as a “Pending Payment”. This is so if a transaction fails or gets aborted for some reason, the user can always make a new purchase attempt without having to make a new request which in turn would create a new pending payment. This is also used for manual payments where an administrator or staff can manually mark a request as paid.
You can access all currently pending payments on your website under the myCred menu in your admin area. You can select to edit a pending payment or take actions such as mark a payment as paid which in turn pays out the points to the buyer; or select to delete the pending payment.
myCred uses the WordPress comment system to keep track of events related to a pending payment. This is mainly used to indicate potential issues and are usually triggered by a payment operator informing your website of an issue regarding a payment.
In most cases however you will not see a pending payment or a comment. This is because in most cases when using instant payment operators like PayPal, by the time the user has been redirected back to your website after a successful payment, they have already received their points. This of course only applies to situations where the payment operator informs your website of a successful payment quickly. As an example, Bitcoin payments can sometimes take time to be confirmed which means a user might need to wait to get their points.
For this reason it is important that you inform your users that payments can sometimes take a few moments to complete so they do not attempt to make a new purchase thinking the first attempt failed. A pending payment is not deleted until it has been confirmed to be paid or until it is trashed.
Since version 1.5 you can use the mycred_buy_pending shortcode to show your users their pending point purchase requests. They can select to cancel these pending payments or select to revisit trying to pay for the order.