What do I do if someone accused me of robbery 3rd degree just to get money from me?

Hello, I'm a defendant who's going for trial in a robbery case in 3rd degree. The person pressing charges was my friend. The only reason he's doing this is just to get money from me. I got text messages from his phone asking for money to drop the charges on me. And if I don't he said he's gonna press more charges. He's been calling me but I don't answer his calls. He has been going to my job to ask me for money. What do you think I should do about this situation?