Contact
Corrections are the most useful thing you can send. Point at the source and it gets fixed.
Report a correction
If a date, a placement or a connection on the map is wrong, write in with the title, what is wrong, and where the correct information comes from. Corrections that cite a source are applied quickly; ones that cannot be verified are held rather than guessed at, which is the same rule the rest of the site follows.
Rights holders
GeekTimelines is an unofficial fan project and is not affiliated with Marvel, The Walt Disney Company or any other rights holder. If you represent a rights holder and want something removed, write to the address above and it will be handled. Credits for the data and artwork used here are on the about page.
Method
Before writing in about a placement that looks odd, the sources page may already explain it — several placements are disputed and are flagged on purpose.