missing folder

I created a personal, free Zoho account recently. I forwarded mail from the inbox of a British (BT) email account I intended to close, to my new Zoho inbox. I created folders and put all this 'old' mail into appropriate folders, so I could refer to them later. This all appeared to work, but I have just noticed that all the folders have disappeared, and of course I cannot access the emails stored within them. Have they been permanently deleted? Are folders only for business, paying, users? Is there any chance of getting them back please?