Help asap

I’ve written about this a lot of times, but is still happening so I really not know what to do.

My boyfriend and I have been together for 7 months, when we were not official, a girl with a fake ig account texted me saying that my guy is cheating on me. We argued and he explained to me that she did this with his last ex too, she even hacked her ig page and take some pg18 pictures 😂 of their ig chat! She threatened both of them to leak those pictures if they did not break up. The second time she texted me trough Facebook with a fake account too, because i deactivated receiving messages from strangers, and she told me that he still cheating on me that she can hack into my boyfriends account and show me proof. Today, I got a text from her saying that he is still with her, that he is cheating on me. All this messages have been trough fake accounts! Today I almost believed her because she was very detailed.

I do believe in my boyfriend but I don’t know what to do, I dont know if i should believe her or not, i also want to receive my parters phone but i know that that is toxic.