Booking.com — Flight booking

I made a booking to fly to Nice with my wife. Your reference[protected]

On 29 May I received an email titled "Sorry. we couldn't book your flight to Nice"
The email said that any charge would be refunded and recommended that I search again for a flight. The exact words were:
"If you still want to book a flight to Nice, you can search again."

In view of this, I did another search and decided to use a different agent and a different airline for my journey.

My bank account showed that Booking.com had taken out £726.54.

As the first email stated that £726.54 would be put back in my account in 2-5 business days I was not concerned.

However, I now find that they have no intention of refunding the fare and somehow you have rebooked the cancelled flight without my permission ref[protected].

I have used Booking.com for many years and reached Genius Level 3. I have received excellent service .

After speaking with their customer service agents many times over the last few weeks I have not received satisfaction.

I accepted that they had cancelled by booking and, accordingly I booked again with a different airline.

I need to resolve this situation as I am £726 out of pocket through no fault of my own.