Hmmm interesting... yes, the contract is not proof of payment.
I was given TWO contracts the night before - one for $X down and one for $X+y down, and I got my total down payment the next day. (I only paid $X the previous night).
Then I had them destroy the contract that says I pay $X down, and the contract saying $X+Y went live.
Point being, contract isn't proof of payment - it is just the INTENDED DEAL all have agreed with, the DEAL happens AFTER u sign the contract.
They won't probably go so far for just $1000 though.. they're probably just scaring you. But in theory, your contract is not proof of payment.
(Curious, why didn't you just deposit the $1000 in your ATM and make a credit/debit card payment? I got so many free credit card payments by making my downpayments via my credit card
)...