Question about product trial that hasn't paid yet...

I was wondering if anyone had any (bad) experiences with a product trial not paying. I did a product trial through Ipsos i-say that lasted about a month long. I qualified for the trial, received the product, tested the product, kept a journal, took the final survey, and received a thank-you email saying my reward would come along shortly (this was back in November of last year). Fast forward to today, and still no money. I've been in contact with the survey company since December. They kept telling me they were working on it, but I still hadn't received any payment. Finally, I got an email from them stating there was no mentioned payment. ... Uhm, excuse me, wtf? Like, I don't work for free. Fed up, I told them I was contacting the parent company (the company the survey was for) on Facebook. :) I didn't say what the product was, but that I had done a trial for them and I hadn't been paid. They asked me to continue any further contact through private messaging (which I did) and are investigating the matter. Today, I received an email from i-say saying I violated ToS by contacting the parent company on social media. However, the way I see it, i-say violated ToS by not paying me the agreed upon payment for services. I haven't contacted the BBB yet, and I'm hoping the parent company resolves this, but, I'm thinking that's my next step.

What do you guys think? Anyone have any experience with this, and how did you resolve it?

*Add: Thing is, I've done product trials for this company before and have always been paid. I received $52.90 for a month-long shopping observation on water consumption, $30 for a week-long observation on mail I receive, $75 for a three-day group session on coffee consumption... I just don't get why they're refusing to payout now.