Hi,

Odoo.sh takes auto backup daily and if you need to access it, you can see it from the backup's tab, also make sure to have proper access rights(Admin) to the odoo sh project.

Regarding automatic dropping of data, may be there is some custom codes responsible for this issue ? If you think, you can find the real cause of the issue, raise a support ticket and let odoo support guide you on the same:  https://www.odoo.com/help

Thanks