The offer of compensation as entered in the MLS is an agreement to pay. If there are exceptions it should have been signed off at the time of contract by your broker (the MLS agreement is broker to broker). Let the listing brokerage know that you expect to be paid the commission as offered in the MLS and if you aren't paid at closing, your broker will file with the local board or MLS and you have a sure fire win.
_________________________
Broker-Owner Thirteen Years REO Experience
GRI,CRS,CRB,e-Pro
Some days I feel like the bug, other days I feel like the windshield