Apple Card Refund credited to my Apple Account Balancex

Are you saying that your credit limit went up (eg. from $1,000 to $1,050). Otherwise, seeing available credit increase implies a credit to your account.

Do you understand that your Available Balance is directly tied to your Credit Limit? Every time you make a payment or receive a credit/refund your Available Balance increases and when you make a purchase, your Available Balance decreases.