Ok, when you call again don't mention Hilton (or any other chain). Don't mention status match at all.

Make some reservations (even if they're dummy ones you can cancel) so they can see you have stays coming up & say you'd like to do a gold challenge, as you intend to stay at Marriott in the future a lot.

BTW - not all hotel chains do status matches or challenges, so if Marriott has decided not to do so now it's not alone.

But good luck!

Cheers.