Refund of monthly installments not received.

I returned an iPad that was purchased with Apple card monthly installments.

When I placed the order, I paid the tax, then the first monthly payment on the first day of the following month.

Then I returned the product back to the store and received my tax refund immediately.

However, I still have not received a refund for my first monthly payment.

I have contacted both the sales team and apple card support, and they are always saying this is an issue of the other team and just kicking me back and forth.

Any suggestion would be appreciated!