Anyone around Hollywood FL ever deal with tax problems and find real help?

I live in Hollywood and I just got this letter in the mail that basically scared the life out of me. Something about back taxes and that I owe money from a few years ago. I didn’t even know there was an issue. I work as a freelance designer and my income is all over the place, so I guess something didn’t add up? The letter looks really serious, like with dates and a bunch of language I don’t fully understand. I tried Googling what to do but there’s so much info out there and I keep seeing the terms tax relief and resolution but I don’t know what’s legit and what’s just a scam. I’m scared to call any of the numbers I found online. Has anyone local actually used something like this and come out okay? I’d rather talk to someone in the area who’s been through it than just take a shot in the dark. I feel really alone right now and I just need to know if there’s a way forward.