Don't use Booking.com - their Best Price Guarantee is a total scam!
I found my holiday apartment £225 cheaper on Expedia so contacted Booking.com and asked them to honour their Best Price Guarantee offer. The customer service advisor agreed that I'd found an identical quote, and therefore was eligible for the £225 refund. She told me to expect an email from her manager.
A few hours later I received an email from Booking.com stating that there would be no Best Price Guarantee because my claim did not fit their Terms and Conditions. This is a blatant lie. Their Terms and Conditions clearly states that they will refund the difference if the other quote is identical - which mine is.
I emailed them asking for clarification on which specific Term or Condition my claim was falling short, but unfortunately, they have chosen to ignore that email, and are refusing to acknowledge my claim.
DO NOT use Booking.com. It is not worth the risk.