Do I get the price difference refunded if I change my booking?

If you change your booking to a more expensive stay or a more expensive period, you will pay the difference. Is the new price lower than your original booking? Then the amount you paid will remain the same. You will not receive a refund for the difference, as stated in our General Conditions,

Changing or cancelling extras
You can change or cancel any extras you have booked up to 1 day before arrival. You will receive an adjusted invoice. We will refund any price difference after your holiday, together with the deposit.