I received an email from Amazon
" According to our records, you have received 1 order(s) from Amazon Business customers in December 2019 for which you have not yet uploaded an invoice.* The [Amazon Business invoicing policy] requires you to provide a compliant VAT invoice (or a receipt, if you are not legally obliged to issue a VAT invoice) within one business day after shipment confirmation for orders placed by Amazon Business customers"
How do I actually upload it? From where?
This is my only Business Customer, I am not VAT registered. Please help me how to deal with it.