More about HEB:
Got a phone call today from the manager of the local store - the one where I bought that disgusting "casserole." I didn't take the call because I was sleeping late (very late), so he left a message. He enthusiastically apologized for the bad experience and invited me to come back to the store for a refund. I won't, because it's just not that important to me.
In any case, I'm happy about HEB's handling of the matter. I only hope they improve the quality of their casserole, but they probably won't.