Commission not paid to me

[David Blue]

I'm a RE broker and initiated a P&S contract in feb 2016 for an investment property. That cash contract fell through on my part and the exclusive right to sell held by the sellers agent expired in May 2016. I sought conventional financing and approached the sellers agent when I was approved in March 2017. The agent spoke with the seller and told me the deal was back on. The agent never showed me an agent exclusive right to sell listing but did produce an invoice from her firm which stated the commission amount, deposit and balance due from the seller for the property. Closing was yesterday and I was denied a commission check. I was told by the sellers agent who was absent at the closing that the seller had reneged on signing an exclusive listing and as such there was no buying commission to be awarded. One of main incentives for the purchase was my 2.5% commission. I feel the sellers agent misled me all the way to the closing and owes me my commission. In fact I hate to say it and have no proof but I think the sellers agent stole my commission. Do I have a case?