He promised to do "everything he could do" to stop it. He didn't promise to single handedly achieve that since as a single vote, he couldn't. His single senator filibuster, hated by both the Democrats and GOPe is proof of that. No one did more than he to stop it.
The fillibuster was an egoistic joke. It was self promotional only; it didn’t change a thing, and was a foregone failure. It, plus the soccer balls and teddy bears, are what turned me into a *former* Cruz supporter.
Cruz is a grandstanding gadfly who is a pariah in his own party. He was not the only senator that wanted to repeal Obamacare. If he truly wanted to do something significant, he should have used his interpersonal skills to devise a course of action and convince them to join him. The filibuster was just some more self-promotion and one of the few ways a first term, back-bencher senator could receive any public recognition. Just tilting at windmills.