The contract I signed said they would deduct around 100 USD a month from the third month of service. So, if you leave any time during the first three months you would have to pay everything back... not sure about flight ticket home as this wasn't stated in the contract.
But! I was told by someone they have changed the contract, which depends on your nationality, that if you leave any time in the first year you have to pay a certain sum (then it doesn't matter if you have been there two or eleven months).