Elan Max Cash – Furniture Bonus Category

I got the Elan Max Cash Visa Signature a few months ago, and I set one of my 5% bonus categories as furniture stores. Planning to make a purchase from a website called Cabinfield Furniture. I made one small purchase of some wood stain samples from them in February, and when my statement came, I didn't get the 5% cashback, only 1%. The app shows the transaction coded as "Office and Commercial Furniture". I called customer service and they said I will have to wait for a letter which could take a month to arrive to tell me why I didn't get the bonus cashback. Does anybody know what MCC's they do consider "furniture" for the bonus category, or why this may have happened? I'm holding off on my larger purchase for now. Anybody have ideas?