I just got off the phone with a manager at Marshalls. He wanted the name of the representative that I spoke to, but I unfortunately didn't notice the name tag in the midst of my rage.
Anyway, he offered me 10% off my next purchase at Marshalls, which was nice (though not enough, in my opinion), but then also needed to know when I was planning to go shopping there again because he has to be there. Instead I asked if I can bring in my bathing suit receipt tomorrow evening to get the original discount I was supposed to get for not having bottoms, along with the 10% for my troubles (which still isn't enough, but right now I'll take what I can get, you know?). So that's what's happening. I'll let you know how it goes.