I had something similar, a while back.
I use a local selling page on facebook, to sell some personal items, so I set up a different account, in a name different to my own. I didn't have any friends as it was purely a selling account, that I very rarely used.
My mistake was to call myself, "JC's selling page". I had the account for a couple of years or so before I received a message from Facebook very similar to your's, informing me that as I was a business, they'd converted my account to a selling/business page.
I tried contacting them, explaining that it was not a business, but got no joy.
This account is now useless and I lost all my messages and photos in the transition.
I've now made another account, calling myself another fictitious name, but something that looks real, so as not to draw attention to it.
I sent them a copy of my driving licence (with confidential info blanked out) to prove my ID.
I wish you good luck in getting your account back, as your case is different to mine ..... but don't get your hopes up, just in case .....