Purchased Zoom Webinars and it charged my card but.. no access to webinars

I have run into the same issue.

I suspect that although you have paid for an webinar, you have not actually assigned the webinar licence. Zoom does not do this part for you. You will need to act as the account admin and assign the  licence to your account.

https://support.zoom.us/hc/en-us/articles/360028938451-Adding-existing-users-to-a-paid-account 
Regards

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