Royal Mail, UK, to invoice me, the sender, for payment of duties and Taxes

Royal Mail have a charter from the UK government to collect customs duty and VAT. I airfreight products from Australia to Amazon UK. by our national carrier Australia Post. who link with Royal Mail for delivery within the UK. Royal Mail invoice the receiver for duty payment. Amazon do not pay duties I have contacted Royal Mail to invoice me, the sender, for payment, with no result. But this is revenue, so there must be a way of paying taxes I assume with an EORI number, this may be possible to be notified, with duty payment through Royal Mail e-invoicing I require someone to give an outline of the process and assist completion of the project