[citation][nom]bunga28[/nom]"There was a ton of rumors about Microsoft’s keynote speech last night and unfortunately, not all of them was true." I fixed for you. Thanks for playing.[/citation]
Jesus. Did someone pee in your cereal this morning?
Since you decided to be a dick, your "fix" isn't even accurate - Jane's sentence was correct as written. The first usage of "was" is (arguably) accurate, as the subject in that case, "a ton of rumors," is singular, even though there are multiple rumors ("a ton" is a collective noun, which takes a singular verb even though it automatically suggests a group).
In the second instance, however, the subject ("not all of them" - i.e., the rumors themselves) is plural. As such, it commands a plural verb - "were". Therefore, "There was a ton of rumors about Microsoft’s keynote speech last night and unfortunately, not all of them were true," is entirely accurate.
If you're going to play internet grammar police, you ought to make sure that you're correct.