It really depends on the app. It's best to contact the app support team/developers directly.
Sorry to hear! What was the name of the app that you installed? Depending on the app developers, they may be able to assist you in prorating the remaining time that you had on their app for the month of August. In that case, reaching out to their support team would be the best course of action.
If there is anything else I can help you with, please let me know.
Gotcha! Now, are you trying to get a refund on the most recent bill? If so, one of our support advisors would be happy to help via email, or live chat to see what can be done regarding a potential refund. You can get in touch with one of our advisors from our Shopify help center to start that process.