The offers we have at the moment are 6 months free Disney+ which you can claim here: https://www.samsung.com/uk/boost/disneyplus/
And you can claim 50% off a keyboard cover, but you would need to buy this at the same time you purchased your Tab.
Welcome to the Community!
I feel your pain. I upgraded to the s8 ultra a few days ago so missed out on the ear buds. Then found out from today you can get a free keyboard cas so people like you and me loose out. So much for rewarding loyalty