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.
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.