I integrated Zoho CRM and Zoho Books each other as two-side sync.  I have synced Vendors, Contacts, Products, Invoices, Sales Orders and Purchase Orders modules in CRM with Customers, Items, Vendors,Sales Orders, Invoices, Purchase Orders in Zoho Books. I created the invoices on the Zoho Books, but I cannot see them (fetch) on Zoho CRM or opposite. While I see the contacts, vendors, products on both side, I can't see invoices, sales orders and purchase orders. My syncranations are attached in the image. 

Furthermore, I had created invoice as a test invoice in zoho books and I couldn't delete it, Zoho gives me a warning about it by saying "Payments have been recorded for these invoices; hence they cannot be deleted". But we need to delete this invoice and I don't how I can do it.