As long as you received the bulb within the last 30 days, as it is faulty, the seller will have to accept a return.
Ebay have not changed the return process - it is still the work of a few clicks.
About a year ago, they started asking buyers to add a photo.
Just one.
Either take a photo and add it, or use one from the original listing.
Then your return will be open.
If the seller wants the bulb back, they have 3 days to provide a label and if they don't, you go back to the case and ask Ebay to step in.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)