Fingers crossed for you.
Even if you booked online you may have luck with their call centre I'm not sure if they will deal with you in store though but it could be worth a punt.
The other thing you could do is go into your on-line booking as you probably have some kind of unique booking reference number and maybe email the query to them perhaps already having researched a self catering holiday you would like.
Or even just log on to the site in general and sometimes the facility comes up for you to have a live web chat with a call centre operative.
Generally speaking they seem to like you to sort out your quereis the same way you have booked, so if in store u go back to the store, by phone you ring, and if on- line then via the web.
Good luck and let us know how you get on.
xxx