have you rang to see if you can add them now? my friends forgot to book ski school last year and rang the travel company on way to airport and they let them book it...
Hi Mel, just got back from Bansko last week and also flew with Thomas Cook to Sofia. We just told the lady at the check in desk that we had paid for our board and ski carriage on the internet even though we hadn't and she let it us put them on for free. Also our luggage was over the required weight as well but she let that go too.