I submitted a BBB complaint and received a reply from United Airlines on the issue. It was another apology and they actually copied and pasted the reply from the previous post I used.They stated they can't undo what happen but feel badly. What they can do is offer a more generous voucher than $50!!!
I also sent an email to Jeff Smisek CEO and the president of customer relations and vice president of customer operations. No reply from any of them though