Being Billed for Traded in iPhones

After trading in my iPhone 12 and 12 Pro Max back in October for the iPhone 13 Pro and Pro Max through the yearly Apple upgrade program, I noticed a week ago I was still being billed monthly for the iPhone 12 and 12 pro max! I've tried to message few times through Apple support and it keeps saying "Let Me connect you with a specialist" but no one ever gets back to me. What the heck! What can I do to get this problem resolved? I got emails for both the iPhone 12s saying my trade in was a success.

Thanks