Hi! I was recently suspended for posting an NSX. They said that the 3D model I used is different from what is in the License. I wanted to know what I could be doing, or to fix this, or to delete this car for good, and get back to working with my mods.

You need to use that 3d model which is in license shown, not in to your ripped model or what

Quote from guialmeidag :

I was recently suspended for posting an NSX.

I believe it was because:
You had posted a mod that was reviewed, found to be legal and published.
But then you changed the 3D model to a different model, a model which was ripped from another game.
In the mod's change-log all your comments are just "Small Changes" and no mention of swapping the model.
So it looks like you tried to bypass/trick the review system. (Several people have tried that before, for example uploading a modded XRT and then after publishing they secretly changed the model)
That is annoying because it wastes everyone's time.

I think bans for first offense are fairly short, a few weeks or so. So just wait until the modding-ban expires.