Apple Pay Question - Please Help

Hey so I used Apple Pay at Dunkin' Donuts the other day and the payment successfully went through so that I was able to get donuts but as I was leaving the store my phone alerted me that the transaction was declined... So my question is if the payment goes through when I'm buying something but then gets declined by I guess TD bank (this was my TD bank debit card on Apple Pay) how do I fix that? Who do I pay and how?