Did not receive my trade in amount

I bought my iPhone 12 on line via the Apple store and picked it up at an Apple retail location on Sep 25, 2021. I traded in my iPhone 8 at the store that same day and got a receipt for trade in value of $190.80. I then got an email from the Apple store requesting that I mail my iPhone 8 but I ignored it since I had already traded it in at the retail store. I had even checked that the $190 showed up as a credit on the card I used for the trade in transaction. I then went back into my credit card statement a few days after receiving and ignoring the email from the official Apple online store and the trade in value credit of $190 was no longer listed in my credit card transactions. I believe Apple mistakenly took back my trade in credit. What is the best way to remedy this issue and receive my credit. I have a copy of the trade in receipt from the Apple retail store.