How payments and OpenAI work?

I checked plans.
Decided 25 pages is not near enough for my tests. Decided I need to subscribe. I was assuming that trial period will start. Upgrade button send me to stripe. Stripe, without any additional authorization, showed my leanpub email(I paid for some leanpub books via stripe) as “payment” email and didn’t allow me to charge it.
I confirmed subscription
Got charged (as in ‘bank’s app see charge’), got payment confirmation on leanpub’s email(instead of trial start).
Memex still shows me I’m on free plan.
Also, when I tried to use my own OpenAPI key - it’s not possible to enter this key anywhere.

Also, sync doesn’t appear to be working between
I try to use specific e-mails for every site for security purposes.