Rise Gardens Advertising scam Skokie Illinois

I received a hydroponic garden system as a gift in late October, set it up and loved the system. Around November I mentioned my satisfaction with the system to a technician who sent me a code to use as a referral bonus, $100.00 to the new customer, $100.00 to me for ongoing nutrients/seeds, etc. with no expiration date. In December I gave the referral "key" to my friends husband as he was going to give her one for Christmas. In early January they purchased a $700.00 system. Since then I've been trying to get an answer regarding how to use the bonus key and have been given the runaround, including the coupon is expired! (Again, no expiration on the code. Had there been an expiration date, which we had no way of knowing, she would definitely have purchased it by then. Give us the rules and we can play the game.) That's less than two months to receive the system, set it up, decide its worthwhile, give the code to a friend and have them ultimately use it. Remember, this is for growing plants, a slow process! 
I have reached out to the company multiple time to resolve and they have just stopped responding.

I have a photo of the referral key email, just don't know how to attach it.