I am working on that intergration and I can correctly submit the data but I need a way to checking if the submission was approved at a later time. Do you recommend using a scheduled script to retrieve that information or do you pose another solution? Or can you trigger a script to fire based on receiving an email?

I would edit your question since not everyone is on the same page about your solution. Script types, record types, and entry points and almost always a safe bet when posing a question. More specificity around "a later time" as well.