Save all of the tik tok videos, and IG vids... anything that him or his friends post about you that can even be misconstrued as bullying! Including all the texts you still have. That way if they were to try and harm you in any way... you have an air tight case.

Do not make false accusations about him, such as yall sleeping together and such.

The reality is you may not get the necklace back, and that's an expensive lesson to learn. You seem to have a good head on your shoulders. Your still crazy young. Your gunna find quite a few more loves out there before you find the "one"!... take it easy... you have time!