Hi alizeh,
Please don’t be worried, the fact is this happens a lot. I could tell you countless stories how this same situation happen to me. You do learn from you mistakes(ex. getting all contact info besides social media accounts) but this not your fault by any means. Facebook has had a lot of problems with accounts being hacked and misleading faces.
Just out of curiosity, how long would it take you to make the cake and finish it by the 23rd? That’s how long I would wait until no contact was made by the client before I say no. Also did you give your house address to them or meeting the client somewhere else?
Personally like i stated before, if there is no contact made before a specific date when to start the project i would not do it, the last thing you want is to waste money on ingredients.
Matthew Kirshner