Good morning Barry,
Thanks for your message.
The adviser was unfortunately wrong about the Visa, you will need an ESTA or Visa Waiver as you are flying into JFK Airport. You should have been offered this service at your time of booking, you would of then received your visa pack along with your 15 week paperwork. As this wasn't offered then its reasonably urgent that you call our contact centre who will be able to do it for you in good time, there is a cost, its £29 but that will see you set and ready to go.
I am happy to point out that there are places online that can do it for you for less but I personally have never used such a service and wouldn't be able to offer any guidance.
Anything else,
Please ask,
Ben