Hello Charlottesh,
I have searched high and lo but I have not found a single reliable supplier for Celine bags. There are quite a number online but I highly doubt that they are selling authentic Celine products since most of them are either based in China or newly created sites.
Some brand names and products are just not available through wholesale channels, unfortunately. Celine is one of those, they seem to have limited their distribution through their own site/s and stores.
All the best!