I think what you are experiencing is par for the course. In 2009 we had $50k worth of damages to our coach in a highway accident and it took several weeks to get the insurer (not GMAC) to officially agree they had an estimate, even though it was the very same one the shop submitted a week after the accident. Then they haggled over a few items (under review, they called it) for a couple weeks, but once they finally agreed they wrote the check within 48 hours. One check for the coach and another for our personal property lost/damaged in the accident.
2004 American Tradition; 2013 Buick Verano
Homebase in the Ocala Nat'l Forest near Ocala, FL