Having one account and using the bonus is not an abuse at all unless he is found guilt of using more than one account.
This is my initial thinking too. And not paying over $10k only because of using bonus with a very small odd seems to me too much. So far it does not seem there is a claim for Multi account. Let's see what the official has to elaborate more about the case.
Few months ago similar cases were coming against a specific sportsbook. I can not remember if it was Rollbit or another one.