There's two choices here. If you do not accept the offer, after you die of old age, the planet will be hit by a meteor large enough to destroy it completely. If you choose to accept the offer, you will be taken immediately to a hellhole, where you will suffer eternal torment in which you will experience forever. This torture will never stop, it will continue even after the universe ceases to exist. You will never get used to the pain, it will be unbearable to the point that if a living human sees what is being done to you, that person will die right then and there. Will you choose to save the planet or will you deny the offer and live the rest of your life, but dooming everyone after your death. The planet's population is 7 billion.