You have to contact the support for a refund
The idea of this page https://fizz.ca/en/contact-us is to explain how you can access the chat bubble. If you do a search in the Solution Hub related to your issue and access the help page the chat bubble will appear at the right corner.
If the chat bubble does not appear, this means that the number of sessions waiting for our answers surpasses our processing capacity. If that happens, send us a private message via Facebook Messenger or Twitter.
Login your Fizz account, check your transaction history. Does it show mulitple payments?
If there is indeed an issue, you need to contact Fizz support.
Open this link https://fizz.ca/en/faq/resolving-issues during business hours
and click on the green chat bubble (bottom right) to start a chat.