First of all, let us acknowledge that you're claiming I "stole" your fan fiction title, when I wrote Star Trek: New Horizons (my version) in 2009, that's over a decade ago, and has been posted (not on FFnet, as that wasn't really a thing when I started writing fanfiction). Also, honestly, there could be a less rude way in which you could ask this.
However, you're in luck. I know longer care about that fanfiction series, since it's been close to 10 years that I wrote or updated it. So, I'm just going to change the name as an act of kindness, and hope you take this as an opportunity to be kinder to fellow fans who might just happen to come up with a similar name (either before or after you) purely by chance. It's not out of the ream of possibility that two separate people come up with similar names for a Star Trek fanficiton series.
Hi guys. Apologies. I'm a bit late to the party. This appears more of a disambiguation issue between same series titles and same series types. See Star Trek: Horizon as an example. Those are both fan films differentiated by year: