Apple charged me twice for the pre-order

I pre-ordered the iPhone 15 Pro Max. I used my Apple account balance+Apple credit card for the payment in the first place. When I check the order status serveral hours later, it said my order was on hold, since they could not charge my credit card(obviously, it meant my Apple card), and asked me to call 800#.

So, I made the call, and asked the rep to use my Visa credit card to replace the apple card for the amount which my Apple account balance could not cover.

2 hours later, I received several emails from Apple, saying my payment method changed, and my pre-authorization is being released. Then, my Apple Card got charged for the same amount which my Apple account balance covered. But, my Apple account balance did not come back, still zero out.

Call 800 several times, all reps confirmed that my account balance went for this pre-order, but no one knows why Apple charged me again for that amount.

Anyone came across this situation before?

Thanks.