Any way to remove a gift from account?

The cards come from the Rover store yet the money is in your Rover account - I think you are screwed but reach out to both support teams for help

Store https://store.rover.com/contact_us
Rover support @ [Edit: Rover’s contact options have changed. Visit the Rover Help Center at https://support.rover.com/ to find the phone number, help articles, or chat with the team]