Failure to respond to & deal with constant emails

I have booked with Netflights, flights to Florida also accommodation at three locations in Florida and Car Hire. Due to a change of flight dates by Delta, I needed to change hotel dates as well. This may or may not have been done because after numerous emails requesting details of the changes made I have not received any update from Netflights and I am left with the uncertainty of not really knowing if the amendments have been made. The booking reference that should open up the booking account on their website shows that the booking cannot be found.
This has left me very angry with the very poor customer service I can either cancel the booking and loose my deposit or continue with my so far fruitless attempts to make contact with a totally inept and intransigent set of people in the so called Customer Services Department.
I would not recommend this company to my worst enemy and will never use them again.