You can terminate the contract directly without the agent since the agreement is really between you and your helper. You should give her the notice period stated in your contract (usually one month's salary in lieu if you want her to leave sooner), settle her salary and repatriation costs, and then cancel her work permit through the MOM website yourself. It is worth checking the MOM website directly for the exact steps since they have a clear guide, and you do not have to rely on the agent at all for this part lah.