We only integrate with Stripe and Paypal so you're best to contact these companies directly if you have particular questions.

However, one common question was how to see if a student has paid/failed to pay their subscription in either of these systems.

See how you might use these reports:

Stripe 

You're able to see on Stripe where payments have failed from the Payments dashboard.
​

PayPal

Paypal explain their recurring payments dashboard in one of their help documents here

You can use these reports to quickly see whether accounts are active or cancelled.