When I ordered my Hermes AW3 I had my Apple Pay declined. I had enough money - so I tried it again, and again through the online order system. Santander told me it was fine. No reason to be declined. Apple told me it was down to the bank. They tried it manually and it didn't work.
In the end I moved the money to another account and used the debit card for that account - and it was still declined. So called Nationwide - no problem with their end - eventually after literally trying it myself 7 times it worked.
I guess the thing is just keep trying. And hope that if its doesn't work and you need to leave it for an hour or so it doesn't delay your order. And to be fair I think with in store pick up it won't - I am sure those phones are pre-allocated to the store and will be there in store for you waiting so as long as you pay before your order is cancelled (10 days) you will have that phone allocated from stock. However delivery to home is different as Apple won't ship it until its paid for and several hours could push your order from Friday to the next week.
