Partial Refund: Taxcloud cannot handle a partial refund like nop commerce. In the event of a partial refund you will have to manually do the refund in the taxcloud portal.
Tax Exempt: Taxcloud see’s tax exemptions based on customers only and not products.
Tax exempt certificates is currently operational and working. You can create tax exemptions on a per customer basis only.
It is not possible to configure a product as “tax exempt”. If a product is marked as tax exempt in nop commerce it will simply ignore this order item when calling the taxcloud api. You can only apply tax exemption at the customer level.