You have no right to claim that. If you learnt arabic and then read the Qur'an then you can make that judgement but not if you do not know arabic. If the english translations provided by others are insufficient then you should learn it yourself and then see whether the writing is unambiguous or not. I doubt you will make the effort for that but if you do then you wont have the same judgement.
Theoretically speaking if we lived forever we obviously wouldn't expect an afterlife. But if we live and then die then we must be dying for a reason. Everyone dies, everyone believes in death. If there is no afterlife why is it that every damn human has a lifespan.