I'm sorry but all the payments are set up automatically with Shopify.
What we can do is give you a refund if you want to try the app longer.
To get a refund you have to first email shopify to ask for the refund.
Send them an email with the link below.
https://help.shopify.com/en/questions#/contact/email
Next they will send us an email and we will approve the refund.