If there's an expectation of payment, that to me would be payment.
If you are communicating about an existing law to acquire a better understanding or to be in conformity, that wouldn't be considered lobbying. If you are communicating, even if you were paid to be in conformity or to get clarification on a particular law or regulation.... It's when you are communicating to change that particular law or regulation that the issue of that becomes a registerable activity.