Believe it or not, approaching you BM has already hurt your chances of promotion in this company. In their eyes you're complaining and "not part of the team." Also keep that in mind if you talk with HR about it you'll probably get your hours back, but it will come with the ERAC version of career suicide.

I'd do two things immediately:

1) Don't clock out for lunches you don't get. After you input the hours you work in RALPH, hit the print screen button and document what you just entered. If management wants to take away a lunch you don't get, let them be the ones to change it, then print out any changes they have made. Repeat this every week it happens to you and have these somewhere at home in the event you want to pursue this once you leave ERAC.

2) When you do get a lunch, LEAVE THE BRANCH.
Seriously- in this environment, you need some time to just refocus, and it's not going to happen if you stick around as it looks like you've learned. Just keep in mind that management will probably be pissed off when you do this (see career suicide above), but I wouldn't even mention it. Just leave as soon as you start your break.

Lastly, even if it is a "policy" of theirs to exchange pizza for hours worked, it's not exactly legal.

Good luck with all of this. Most of us have been in your shoes before and it sucks. Let us know how it works out.