No tax invoice available

I've been trying to get a tax invoice from VWFS for the last year and have been unsuccessful. Between at least 2 dozen calls and emails I have received the invoice the dealer made to them, an amortization schedule and a tax certificate not quantifying the VAT. SARS wants a tax invoice with the words "tax invoice" written on it, our company details, the value of the transaction and the value of the freeking VAT. Why is this difficult.