Buyer agent commission

[Charles Shils]

I listed on MLS through entry only
Buyer came in with agent
Buyer had no written contract with agent
Agent submitted formal offer to purchase
I refused---It was too low
Buyer came in with other agent and submitted a higher offer
I accepted
First agent now says that according to MLS rules I owe first agent the commission because that agent procured the buyer and was in middle of negotiation
Second agent says that buyer was not satisfied with performance of first agent
Again, first agent had no written contract with buyer
Is first agent due a commission??