You'll need to provide a little more detail than that if you want assistance...

However, Bitcoin transactions are irreversible - the only way to get your coins back is if the receiver spends the coins back to you. In your case, if you've already sent deposits twice to the exchange (I'm assuming that's what you mean by resending money), you'll just have to request a withdrawal from the exchange for the amount you want back. It's highly unlikely any exchange returns funds to users. To my understanding, even if you send amounts below their minimum deposits, you won't get it back without intervention (with customer support).