You can enable the customer login/registration on your store by logging into Shopify admin>Customers> Click on Edit settings (scroll to bottom)> Choose one option on the right (refer screenshot).
Go to Shopify admin --> Settings -->General -->Store currency Add under - HTML with currency <span class=money>${{amount}} USD</span> HTML without currency <span class=money>${{amount}}</span>
Refund is not an option. We will not be able to refund you partially or in full also as we do not have a refund policy for the theme. Alternatively, what we can do is to transfer your theme license if you can find a buyer by yourself.
You need to send us a request with your email used at the time of purchase. You can also use our updater app to install a new version of the theme here: https://ecom.flyingstartonline.com/theme-docs