Sounds like a mod conflict. I use Fracking Universe so I never tried Project Ancient Cosmos; and the mod says that the planets added are basically the same as FU so theres no reason to use both.

Don't refund it if you are going to buy it again.

i dont have Fracking Universe and have never had it

That's a problem with mods that add new planet types. Starbound handles trying to remove them badly, I think it keeps trying to look for the new planet types, then crashing because they don't exist anymore.

If you want to start the whole game over without Project Ancient Cosmos, go to Starbound in your Steam library, right click on it, go to Properties, Installed Files, Browse, go into the Storage folder and then delete the contents. That'll clear your old universe and characters.

If you want to try to keep the character, try just deleting the Universe folder from inside Storage. I don't know if it'll work, though. There are also things on characters that Starbound doesn't handle the removal of well.

If you want to continue your current game without starting over, I think you'll have to reinstall Project Ancient Cosmos.

I have done some tinkering with the files and nothing has changed. It would be nice of files said if they are corrupted or not. Reinstalling the mod that broke my game i have already tried a few times. At this point i have already sent a refund request and im not sure if it will be accepted, but im still trying to fix the game

I do wonder if steam has a setting for making factory resets of game data. if it does then that would be helpful

Deleting the Storage folder should have reset it to how it was when the game was installed. If it's still broken after you've deleted the storage folder and reinstalled the game, it might be another issue. Do you have other mods installed? There might be a conflict there.

i have no mods installed

Can you show us the log?