Before buying anything, always make sure that there is a refund policy.

Below are emails i've written when i needed a refund from a product that i disliked. Feel free to use any of these as a template for your own inquires.

Company LLC charged me without crediting my account on the
14 July 2017, i request the following PayPal/Credit-card transaction
be fully refunded immediately as well as the termination of all
reoccurring payments/transaction linked to my PayPal/Credit-Card Account. PayPal/Credit-Card transaction ID to be fully refunded: XXXXXXXXXXXXX Thank you for your co-operation. Kind regards, XXX

Hope this helps.