Amazon has a specific problem that it has multiple independent sellers, all creating their own listings. Here's a quick glance of all the assorted images they're using.
So, it's not as simple as giffgaff asking amazon to change their image. giffgaff would need to contact each of the independent sellers to have this changed. And probably amazon itself won't contact them -- indeed, it's likely that amazon's messaging system will start blocking giffgaff as a spammer if it tries to message more than a few of them without actually buying sims from them.
Ebay has a similar problem -- multiple independent sellers all creating their own listings and using different and possibly obsolete images -- and again, its unlikely that ebay will contact the sellers on giffgaff's behalf and very likely it will spam-block trying to contact them individually without buying sims from them.
I'm flagging this thread to an educator, because it's otherwise unlikely that the appropriate staff member will see it.