Correction for release date rejected

I've submitted a contribution to correct the release date of our own short film. It's 2014 now. Imdb put it up in 2014 because I contributed the information than, when we wanted to release the film. But it didn't happened, because we had post-production problems (ran out of money), so the release had never happened. I collected some money last year to finish the film and now we will release it this year. So I submitted this correction, but IMDB rejected. They wrote: "We believe the data listed is factual, as such we cannot remove this as requested." Then I've sent an email for IMDB customer service asking about what kind of official document they need to accept my submission. (like official written signed statement from the producer, etc.) And they answered the same general sentences: "It is our policy not to alter or delete any kind of correct/factual information or credit from our records. We have reviewed your request and believe the information we have listed to be factual, as such we cannot remove this from the database." So they did not even give me any chance to prove that I'm right. They did not interested that I was the one who made the film so I know what happened with it. Can somebody gen any idea how to solve this? Many thanks in advance. :)