what do you think of this ruling? (B&M donkament)

[myxomatosized]

so here's how it went down. at the final table, i'm in the big blind, the small blind gets knocked out. so on the next hand the button skips him and i'm supposed to post the small blind on the button (small, small, big). the dealer doesn't tell me to post, so we just have a small and a big as normal. some guy shoves all in, everyone folds and as the dealer is pushing the pot he looks puzzled and then tells me i was supposed to post a small blind. even though he didn't tell me to, and the hand was already over, he wants me to forfeit my small blind to the guy who just won the pot.

what do you guys think should have happened in this situation?