Thank them and confirm the course
Name the course and the purchase date so they know you found the right order.
Check it against the policy
Look at the refund window and how much of the course they have used.
Ask what went wrong if it helps
One short question can show a fix, such as access trouble, that is better than a refund.
Decide and say so plainly
State yes or no in the first lines, then the reason.
Explain the refund timing
Say when the money should arrive and which payment method it returns to.
Close the access
Tell them what happens to course access after a refund.