No one has refused to deliver anything - - David's Bridal website clearly states "catalog will ship within 2 to 3 weeks", so let's do the math - - you ordered it on August 1st and three weeks from then was last Tuesday, 8/22 and today, the date of your complaint claiming bad customer service, is 8/24.
And you're correct - - time is something most brides cannot afford to waste, so that is why planning ahead and allowing extra time is so important.