Stickers fall away

I have been playing this game for more than a month to help my daughter to fill the sticker book. On March 23 we had 3 stickers on each page but yesterday, without a reason that I can point, about 25 stickers just disappear.
Its very hard to collect this stickers. I have collect everyday 4900 coins.
What can you do to help me have my stickers back??

memelinasp about Strawberry Shortcake BerryRush, v1.2.2