Credit order

Matilda: Projects with designations such as (completed) will always be at the top of one's credit list, until they are released (in which case they will be placed in the order of their proper release year) or deleted from IMDb altogether.

If the film is never going to be released, you can request that it be deleted from the database. To make this request, go to https://help.imdb.com/contact and make the following selections in order: "IMDb Contributor", then "I need help and haven't submitted an update", then "Titles", then "Delete a title". Then click the "E-mail" button to be able to e-mail the IMDb staff about this. 

On the next screen, there will be a form to fill out in the e-mail, which you can complete as follows:

Please include the following information (where possible):

Title to be deleted: Limbo (2017/VI)
IMDb URL of the title: https://www.imdb.com/title/tt6769120/
Your Relationship to the Title (cast, crew or contributor): cast
Reason for deletion: [Here you will put an explanation that the project is not going to be released. Provide all the evidence you can to convince the staff that this film should be removed from the database because it will never be released.]

When you are done, click "Send e-mail". 

I hope this helps.

I found it and submitted a release date based on it's upload date to the Director's Vimeo.

https://vimeo.com/210514507

Edit: Problem solved. :)