If (like me) you bought a steam deck right before the announcement of the OLED version and the price drop for the original, you can contact steam support, tell them that if you knew about the coming price drop you would have waited, and request a refund for the price difference.
I paid £369 for a refurbed 256gb steam deck, then they lowered the price to £279, and I just got £90 refunded to my steam wallet this morning after contacting them yesterday.
I put in a support ticket at 1am last night, still to hear back. I only received my 256 refurb yesterday afternoon too.
I’m more than happy with the unit, just annoyed that it’s cheaper to buy a new unit this week let alone the £90 price drop in the refurb.
I think since you opened the support ticket within the return window, they’ll respect it, even if it takes a while for them to get in touch. I remember reading that somewhere in valve’s ToS