Perhaps try this :
If the seller doesn't ship to your country, you may be able to use a reshipper (cross border shipping company)
eg If ordering from a US based ecommerce site then find a reshipper with a US office.
Use the reshipper's US address when ordering on the ecommerce site.
The reshipper receives the package, then forwards to you.
If the reshipper needs an invoice for customs declaration, then print it from the ecommerce site as a pdf.
Try searching for "cross border shipping company".