Same issue – i’ve had a premium subscription for some time. My credit card changed, and the auto-pay bounced. So axcrypt told me to change my payment info. Which i did. Then – nothing – there’s no way to actually get axcrypt to now do a transaction.
When you navigate to an option that says “upgrade me to Premium!”, it just links back to the account page that says “update your payment info” (which is done at that point).
There is also no help available- since that is only available to paying customers.
So perhaps time to look for another service – one that actually will take your money…