In that case, there was almost certainly no willful intent in his continuing to take the deductions out of your check, or, for that matter, in his failure to notify you. Late payment cancellations are almost inevitably done retroactively; i.e. if he didn't make the payment due February 1, the company wouldn't cancel the policy until sometime in mid-March. During that time, the policy would be in effect, and the cancellation would be done retroactively.
If this is a first offense, it's possible that the insurance company may reinstate the policy if payment of the back charges are made. It's unusal in the extreme for an insurance carrier of group insurance policies to refuse to accept back payments or allow reinstatements unless the insured (meaning the employer) has a history of late payments to the point of cancellation. If that is the case, at some point (usually the third or fourth offense) the insurance carrier has the right to say, no more, we won't take you back as a client.