messages

I deleted a family members messages on my iphone did the reset and back up and somehow lost two months but then my ipads both lost all of the messages and from a back up it only has the last two months. I thought the iphone was to sync with other devices hence my daughters messages would all come back, even all pictures from years shared are all gone on my ipad, why wont the three devices sync and I have read that the messages are never gone so how do I get them back. I have tried the turn off messages and turn back on and that did not work either.

Hoping to figure this out as I was devastated I accidentally did this.

Looking for guidance,