Man that really sucks, 11 days sitting in a Dayton lot would drive me up a wall. Getting hit with a $250 jump after they already had your car is straight up hostage pricing, they know you can't exactly say no once it's loaded. To answer your question, real pickup and delivery dates in writing are pretty much a myth with most of these brokers. The contract is usually full of "estimated" this and "subject to change" that, so they leave themselves a back door on purpose. Some folks have had luck getting a set date by going straight to a carrier with good reviews instead of a broker, but even then it's never a rock solid promise. Best you can do is get everything in email, save every text, and push back hard on that extra charge if it wasn't in the original quote.