I used my tremendous card at a gas pump and it drained all of my funds

So I had a tremendous rewards card for around $60. I used it at a Kroger gas pump this morning without thinking (for around $20). A few hours later, I get an email informing me that my prepaid card balance is now $0!?

Is there any way for me to fix this issues, or will it fix itself? I emailed Tremendous, but I didn’t get a receipt at Kroger.

Thanks!!