We do offer Amazon if you would like to purchase a Guardian upgrade or a specific Z-Tokens package. You have to go directly to Amazon's site and then choose which upgrade package you want, you cannot purchase an upgrade via Amazon directly through our site. Just search 'AdventureQuest' to find the Guardian and Z-Tokens packages available.
We cannot assist customers with most Amazon payment issues as we don't have access to their system, so you most likely will have to contact Amazon via the Amazon Games & Software Downloads Help Section. They also have a FAQ (Frequently Asked Questions) which includes a link to their Customer Service. Please keep in mind that all sales are final according to the Amazon Games and Software Terms of Use.
If there is an issue with Amazon where you cannot purchase the package directly from Amazon, you can also buy Artix Points using Xsolla who accepts Amazon purchases. Then you cam spend your Artix Points on an AdventureQuest upgrade.