Thanks for your suggestion, sc flier.

I called the Corporate Customer Service at 1-800-328-6242 and was then transferred to Gold Preferred Guest Customer Contact Centers at 888-625-4990.

I was told when I made the cash/points reservation on 2/26, the hotel was already cat4 (since 2/1) even though the spg.com is not updated. Even though I have my confirmation letter showing the rates for cat3, they can't refund me the difference of 60USD/day and 45USD/day.

I believe I am over-charged because of SPG's mistake. I must say I am very disappointed with this.

What's more, I was offered 90 points for the 15USD * 2nights = 30USD which I over-paid. I don't understand the calculation behind this offer, but I was a little angry and refused the offer.

Can someone here please let me know how should I proceed? Thanks a lot.