Broker went behind my back.. What do I do?

[Account Closed]

So I have a listing agreement that started in December of 2014 - May 16, 2015. The listing expired, and I recently just found out that the property went into escrow the end of April, and will be closing next week. From my understanding, this is illegal and the other broker can lose his RE license, and I believe that Im entitled to 100% of the commission. Is this true?? I talked with my brokerage and they say we need to wait until the transaction closes for us to proceed. I'm just a bit worried about the situation, and wanted to get some feedback as to what I should do, and If I am entitled to either the 2.5% or full 5% commission...

Thank You!! :)