New business accounts, old personal debts
I've had a similar problem in the past. Any account that was a business account be it credit cards, loans, or lines of credit are not your responsibility. You did right by starting a new LLC and doing business that way. Creditors take a chance on businesses that's why new businesses have higher interest rates. But even if they pulled your credit for the business accounts it doesn't make you liable.
If you ever wanted to get your old business going again business credit repair does exist, it's just much harder than personal credit repair because the laws aren't as lenient as with consumers.