Yellowstone Capital Refused to pay commission due on renewal contract Internet

Dimension funded a transaction with the account
in question for which it received a commission pursuant to an ISO
agreement.  Subsequently, Dimension funded
another transaction pursuant to the same ISO.
Dimension tracks the maturity dates of all its merchant
accounts in order to pursue possible renewals. 
When following up with the first account, we found that the account had
already renewed directly with Yellowstone approximately
30 days prior.  We asked the account to
forward a copy of the executed documents which they did.  The renewal was for $250,000.   According to Schedule A of the ISO agreement this would generate a commission of $12,500.
I contacted Isaac Stern, the president of Yellowstone
and he asked that I forward a copy of our ISO agreement which I did.  After receipt of same he emailed back that he wanted a fully executed agreement.  The one I forwarded was sent
to us by Yellowstone and signed only by Dimension.  Yellowstone did not return a
countersigned copy of the ISO to Dimension, (which Mr. Stern obviously knew)
however, Yellowstone had previously funded two transactions without a countersigned ISO. 
After, I made a final demand for payment; I received an email from Yellowstones in house counsel
stating that their position was that no payment of the commission would be
forthcoming unless Dimension could produce a fully executed ISO. (In other
words, the one they refused to countersign.)  Further discussions continued with Isaac Stern
and David Glass.  Mr Glass called me on July 11th after Mr. Stern failed to respond to two more emails I had sent and stated that there would be no commission paid to Dimension.  End of story.