Pending activity is a transaction that has not been fully processed, it may take 1-3 business days to process. Once completed it will show in your completed activity history and count towards your available balance. You cannot cancel a pending payment.
Requested activities are transactions that have been sent to your customers, but have not been paid. They will remain in your requested activity until they are paid or canceled.
Completed activity is a transaction that has cleared your account, all completed activity counts towards your available balance. If you find that there is a mistake in your history, you should always reach out to the other party first.