If there is no minimum period of subscription in your contract then you could have it disconnected right away.
If there is then they (Globe) would normally charge you a pre-termination fee. If I were you, maki-usap ka na lang ng todo and make an official letter explaining that you are presently encountering financial difficulties which was unforseen at the time you subscribed and that you will not be able to sustain the subscription in the future. They may take an exception in your case.
Have that letter duly received and keep a copy for yourself for reference in the future.