The statement came a guide for filling the cartridges that I read carefully.
When I wanted to refill the ink, I realized that the Canon cartridges PGI 550 and CLI 551 had not the slightest resemblance to the cartridges depicted in the manual. It would be even with the best will not have been able to refill with the instructions sent the ink.
Only a home page found at the Internet search of another ink suppliers helped further because there the right cartridges and their filling were described in words and pictures.
A complaint via e-mail to this seller here remained unanswered to this day.