So, don't accept the cartridge, demand a refund. If he refuses, please post his name so we can avoid him.
That sounds like good advice Oregon, and it would certainly helps the rest of us to know the seller's name, except if the seller refuses (like it sounds he might) that leaves Ejlif exactly nowhere, and possibly facing charges of false accusation and slander. Negotiation is always the best policy if one has no proof -- which BTW was the same problem you faced.
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