My question involves a consumer law issue in the State of: Tennessee (the company I purchased from is based in Missouri)

I bought e-gift cards from an online retailer. They had a promotion for $30 off a $100 purchase. I used the promotion code on my e-gift card orders and they went through without issues. After the first few orders I noticed the disclaimer that said the promo code does not apply to e-gift cards. Since it had worked for me, I continued placing orders. All of my orders went through and I received the e-gift card codes via email. Basically, what I did was buy e-gift cards at a discount, wait to get the gift card via email and then used that as payment for my next order. I did that several times. Eventually I took all the e-giftcards and placed orders for actual gift cards to be sent to my house via regular mail. The company then cancelled the orders I placed for actual gift cards a couple of days later stating that the promotion code wasn't valid for e-gift cards. Do I have any recourse since the website does not have any disclaimer that states that they have the right to cancel orders if there is an error? It also does not state that gift cards cannot be used to pay for other gift cards. Thanks!