If you are looking for a managed solution, I suggest one of those that you pay for (iCloud, Dropbox, OneDrive) since usually, paid services have at least some form of customer service and something like OP's story is less likely to happen.
[1] Also, the cloud provider where I rent the server might decide to block my account for whatever reason. To minimise the risk, I'm planning to store daily server backups on a different cloud provider.
I dont have a mac at the moment but have a iphone. Their windows application is very bad, unreliable sync and their web interface is missing a lot of functionality. No linux integration at all, but that is expected.
Onedrive works well for file sync but almost have no photo library + editing functionality.