When I booked a day’s car rental with Budget in Germany via the Ryanair website I paid €43.29 (£33.90). However, I have now been charged an additional €250 (£195) plus £5 bank charges.

When I complained, Budget told me this was due to the booking being on a German bank holiday. GH, London

Your booking voucher states that the €43.29 includes all fees, although the terms and conditions beneath do warn that Budget can pre-authorise a whopping additional €975 (£760) on your credit card as a security. Ryanair explains that the €250 was a temporary security deposit required by Budget, which is released at the end of the rental agreement.

Except in your case it wasn’t. Now Budget discovers it accidentally helped itself to a further €50 (£40) “in error”. It promises that the full amount will be returned within seven days.

As for the bank holiday levy, the firm says it has never heard of such a thing.

If you need help email Anna Tims at your.problems@observer.co.uk or write to Your Problems, The Observer, Kings Place, 90 York Way, London N1 9GU. Include an address and phone number.