Ho do I refund the wallet, I transferred in error

I do not think that is possible.

Try to contact the support

To chat with the support, make sure that:

• You're logged into your Fizz account.
• You're active on a help page. https://fizz.ca/en/contact-us
• You're within the business hours: Monday to Friday from 8 a.m. to 9 p.m. (EST), weekends and holidays from 10 a.m. to 6 p.m. (EST).
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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.

Did you contact the support?

It isn't possible without speaking to support. But it can also be used as a prepayment credit for your next bill.

Humm good luck!!!

You can get a refund by contacting (chat) Fizz.
I did it not long a go.