To analyze the issue and assist you further, please send us few sample header details of the genuine messages that got fetched into the Spam folder. To get the message header, open the respective mail in Zoho >> click Show Original icon on the top right corner of the mail window >>Show Full Message >> copy the information.
In regards to disabling the Spam filter, we are working on providing an option to the Organizations Super Admin to configure and turn on or off the Spam filters.
Please send us the header details to support[at]zohomail[dot]com.
Based on your requests, currently we have completely turned off Anti Spam filters of Zoho for the mail accounts of your Organization from our back end.
The option will be soon available in the Zoho Mail Control Panel, after our upcoming updates. You will be able to make your Anti Spam choices for your organization, after we provide the option in Control Panel.
Please forward us the emails with headers which are filtered in spam by mistake (to firstname.lastname@example.org). Because our Zoho Spam filter will filter emails that has certain patterns. If these emails which are marked as spam are identified in any of these patterns we will rectify it and we can resolve the problem permanently with the help of our Anti-Spam team.