Same here. They asked for account details in first response, then screenshot of the charges on the next, then closed the ticket in under 24 hours for some reason, have just sent the screenshot waiting for a response.
Have the same issue and it's an actual double charge for me, I opened a ticket with CS_Agent through the community DMs, received a response asking to verify details. Now waiting to see next steps. Would suggest you do the same.
This was happening to me a few days ago, it seemed to be due to server not able to handle the load. I tried maybe 10+ times and then it worked. I would suggest deleting and reinstalling the app and then try again later.
Thanks @Handy1 !Just posted this from Public's own explanation at the URL: https://www.publicmobile.ca/en/on/get-help/articles/reward-rulesI guess they mean UPTO $20 as the max possible earned from community contributions.