I highly recommend that you call the store and ask for the manager. Ask the manager does the CASHIERS understand the Word of the Day promotion as you have had problems in the past redeeming their offer being promoted on their Facebook page.
From Facebook: Stōk Cold Brew Coffee is our WORD OF THE DAY item on Tuesday (7/7) and you can try it for FREE! All you have to do is put a bottle of Stōk Cold Brew in your basket or cart and say “SToK Cold Brew” at the register! (Limit 1, customer responsible for CRV). Find your store: https://bit.ly/2A4REjm
It appears that only the green or purple bottle of the Stōk Cold Brew Coffee will qualify for the freebie.