But in truth, you weren't playing by the rules. Yes, you never did any of the things that get normal MSers banned by a bank, but you were using a personal account for a business, rather than a business account.
You funneled business expenses through that personal account and reaped the rewards.

When the bank saw that your expenses far outstripped your income, compliance probably got involved and then rat's eyes were on it. It probably didn't take them long to figure out that you were an unprofitable customer.

And, unfortunately, there is no rule that says that a company has to do business with an unprofitable customer.