Amazon Music Unlimited subscription

Hello,

I subscribed for Amazon Music Unlimited and used Apple Pay as my payment method. Amazon Music Unlimited costs $9.99 for existing Prime members, which I am. The confirmation email from Apple pay says I'll be charged $11.99 after the trial period expires. I wonder why there's this difference. Amazon Music website says it's $9.99 for Prime members and $10.99 for everybody else for a single plan. The question, does Apple Pay charge any surcharge for using the service? Even with tax included the price should not be $11.99. I already contacted Amazon Music support and they said my price should be $9.99, and that I'll have to call them back if I'm charged over that amount. What do you guys suggest? I can just cancel it after the trial period and get the service again with my credit card directly, or will Apple Pay adjust the amount eventually?