If you’re an organizer of a group outside the United States, and your event attendees are not being marked as paid, there are a few possible explanations:
Your members aren’t returning to Meetup after submitting a payment
After a member submits their payment via PayPal, they must click a link to return to your group page to complete their RSVP and be marked as Paid. If they do not, the payment will be processed but they will not be marked as Going to your event.
You can manually change a member's RSVP to Yes and mark them as Paid.
You have a PayPal Business account
Your Instant Payment Notification (IPN) is enabled
If you’re using a personal PayPal account, make sure that your IPN is turned off.