I have my SYRX through zecco and fidelity and I can put orders in on both and no restrictions pop up. If it says that a stock is on the chill list/ 250$....it warns you that it might be, to be aware. It's up to you to check the list is my opinion. Buuuuuut yeah zecco sucks, slowly moving all my funds to TDA , no problems there....
is it possible zecco is charging an "NSCC illiquid fee to sell?" that is different from a "non-DTCC eligible" (the "chill list") fee from my understanding. SYRX could certainly be an "illiquid" stock, but still DTCC eligible, imo.
I'm sure you aren't making it up. Zecco is notorious for pulling crap like this. Check out Penson. I moved all of my holdings out of Zecco last year to my Ameritrade acct. You would be much better off with a better brokerage.