How do i get refunded back being charged twice?

I got charged twice on the app, when making payment it charged my card then the app said there was an error. I confirmed booking again and i got charged again.

Whats the best thing to do? i have emailed the help support team and let my pet sitter know if they can tell Rover my payments have been duplicated.

Does anyone know how long the refund process takes as it was quite a lot of money

Thanks

Harriet :)