Opened Pack after MS were released and received a base card.

Hi, I was directed here for a question regarding a base NHL HUT card vs a milestone..

I received a base card when a milestone card was available for the player. After selling him and asking for advice on what to do with the pucks earned, i was advised that i received the wrong card. The one that i should have received is 3-4x in value.

Can anyone help please?

Thank you regardless