Immediate termination of the contract
In all scenarios, the host family is still expected to buy your ticket home and to accommodate and feed you until you leave. This applies regardless of who initiates the termination. Although this is the expectation, just be aware that they may try to kick you out or refuse to buy your ticket. Try to have yourself prepared for this outcome, so if it comes down to that, you’ll be okay. Get home safely and then if you feel it’s necessary, take legal action.
Contract termination is usually a last resort and is a very drastic thing to do. If you are unhappy and want to resign, first try to speak to your host family and resolve the problem. Leaving early can leave the family in a state of turmoil. It will cost them a lot of money to get you home and to replace you. So always keep them in mind, remember, they are human beings with many of their own problems so try to work things out before you decide to abandon them.