Delete credit

I have been credited as associate producer on a film, I have not worked on. Both the director and main producer and myself have tried correcting this and the answer is that I need to provide evidence, best way through an online version of the film. But the film is nowhere to be found online, so what can I do? All answers from IMDb are identical - and no-one listens when I explain the situation. What to do here? I have 46 credits on IMDb which are all correct, and then this one to a film, I have not worked on and which I do not want to be associated with. Best, Henrik Underbjerg