Contract cancelled

On arrival at Atlanta airport with my contract of confirmation in my hand the receptionist told me that the contract was cancelled. The contract was agreed on the amount of $564.08 and a deposit paid of $62.68, leaving the balance of $501.40. The counter told me they can assist, but the amount will now change to $1100.<br> I requested an explanation from \airport [URL Removed] and proof of the refund of my deposit a few times