Demolition at any scale can get very messy - if it is done incorrectly, it could cause damage and affect the structure of the house. An entire house typically takes around 3 days to be fully demolished and an extra 1-2 days for post clean up.
Poor cleaning job, and salesperson cared more about their points than showing any empathy. Overpriced project management company, who will max out your insurance coverage. Hire the contractors yourself and you will save 30-35%.