All the payments are set up automatically with Shopify. What we can do is give you a refund for one month. So you will get highest one month of trial.
To get a refund you have to first email Shopify to ask for the refund. Click here to send an email to Shopify.
Next, they will send us an email and we will approve the refund.
However, You can also use our app for free as long as you are on a Shopify Partner Account.