DP - I had the 20K offer and clicked through to upgrade last month. Yesterday, 10K was deposited into my Marriott account. I sent a message showing my offer letter to prove I should have received 20K and they responded that my offer was only for 10K. Not sure how they can get away with this, but they're trying. In addition, I did receive my certificate for 35K free night into my account, but have not tried to attach it to a reservation yet. I've had my credit card since Nov 2017. I also have the AMEX SPG business card.