Message Thread photos NOT show 0 KB!

Can someone explain to me why/how Apple would delete our message data attachments and photos without consent, warning or notification? This is not OK! We pay premium prices for phone, tablets, MAC, and all the other BS we purchase from this company and we are not even given the common courtesy of the option to keep our memories?? Will they counter this with "Terms of Agreement"?! My device has been 100% BACKED UP for years and Message was never deleted, now they are all showing 0 KB!!!!