"But I subscribed to it again on the same day that it was unsubscribed. "
My hunch was that you were already subscribed on October 16 (Oct -16 - Nov 15) when you accidentally unsubscribed thus, according to the terms and conditions would be charged to you regardless if you opted out before its expiration.
On the same day, you re-subscribed thus the double charge for the same period.
Though Globe would be in a position to assert their rights according to the terms and conditions, I would think that they may understand your situation that it was purely an accident that you unsubscribed.
Just have a request to have it reversed out of goodwill (if the above case is true) and though it might take time for it to be escalated and decided upon, at least it is on record.