I purchased a game (Tropico 5) that said "4 Pack Gift" in the description thinking that I would receive 4 copies of the game with it. I deposited my keys to dispenser, then bid on the game. When I received the trade notification on my steam client, I realized that the game was probably just a single copy FROM a 4 pack instead of an entire 4 pack, so I declined the trade. However, instead of refunding my keys, I keep receiving the same trade request over and over each time I decline it. Is there a way to cancel this trade and get my keys back? I haven't received the game gift yet.

We do not reverse trades for this reason. You should accept the gift and try to contact the seller for refund.