So Sorry to hear that marlyn&kenny.
I think we live and learn in this life. I'm sure you will get your money back with more persuasion.
The amount £1715 is pretty big.
You can check website like moneysupermarket.com for great deals.

We booked our flights for less than £1600 3 weeks ago through opodo. But we went through mysupermarket first to check for better deals. Then we booked it through quidco to get some cashback.

I'm crossing fingers for you to get your money back. It is best to book flights with the accredited websites then you can get a guarantee that they are not fraud.