Haven't reached 6 digits yet, so no troubles. But tbh Mercury has some award scheme for accounts with more than 250k USD deposit. Actually you'll receive a tea. But the point is they not so afraid of 6-7 figures
But you approach an agent as a person, the deal is done between the agent and you, right? Why then pay for agent's services extension from LLC account, if you can just follow already made deal and pay with your private money as ETBUS?
If I were you, I'd start a new one. But be aware IRS may flag you/your LLC in case of previous records. Even if the incorporating will go through smoothly, next April you'll have to report to IRS again, and who knows if they will not associate you with previous company.
I used North West. They can help you with a whole process, but IMO applying for EIN and then for account in Mercury is manageable by anybody who's smart enough to run business.
But of course you can pay them extra to go through the whole process without even moving your finger
Actually even though these "services" are looking like similar, cover different fields,
An agend is just helping you to register your company and is an official POC between you and governmental institutions. They help you with filling papers, give their address for registration but for sure...