never got my money back after I cancelled a payment through apple pay.

Unless it was a payment for an Apple product or service you do not get a refund from Apple. You would have to contact the merchant you made the payment to (via Apple Pay) and that merchant would refund to the credit card or bank you used to make the purchase. And that includes the Apple Card Credit card.

1. Who did you make the payment to?
2. Which credit or debit did you use to make the payment (using Apple Pay)?
3. Have you contacted the company you made the payment to and requested a refund?

That’s the confusion. I was thinking it was a subscription from Apple etc. Please contact an Apple Cash Specialist at Green Dot Bank. Apple Cash is a service that’s administered by Green Dot Bank. Contact an Apple Cash Specialist at Green Dot Bank by calling (877)-233-8552 or by calling 1-800-MY-APPLE

https://applecash.greendot.com/termsconditions/

Did you request a refund for your completed purchase? If not, you may request a refund through the link below.

Request a refund for apps or content that you bought from Apple - Apple Support

So, you sent funds to a friend using Apple Cash? Is that correct?