Did you only have 1 thank you account active?
No. I transferred them to my prestige card which is still open.
This is a quite from DOC.
"If you did the ThankYou deal, you need to do one of the following: use up the points (flights, gift cards, etc.), or transfer the points to your ThankYou credit card. If you choose the latter, you’ll have 90-days to use them up before they expire"