Games : Minion rush challenges from others

When I'm sent a challenge either random or from a friend, I click on that persons name. That brings me to a new window with three choices, with tokens, it appears if I click the token then I send the challenge but I don't want to send that challenge because that I be leave cost me tokens. I thought they sent me a challenge .even though I haven't sent the challenge or accepted it those tokens have been removed from my token bank. How can I get them back. I think it should give you the option of changing your mind. I clicked on multiple options hoping to reduce the token amount but it actually took them all. Help