Need help from a Londoner re my Christmas at Kew tickets

Probably user error but I need help. I have a confirmation letter for my tickets for Christmas at Kew, a reference number, and the number that will appear on my credit card. The letter says my E-tickets will be attached to the confirmation email, or I can download them by logging into the customer service area. There are no E-tickets attached to this confirmation letter, and I can't find anything else on my computer from Kew or See tickets. I also can't find customer service on the Kew website. I will try calling on Monday, but I'm leaving on Tuesday. Can somebody tell me where to find the customer service area on Kew's website? Many thanks!