Exactor

noun

1. One who exacts or levies; specifically, an officer who collects tribute, taxes, or customs.
2. One who or that which requires or demands by authority: as, an exactor of etiquette.
3. One who compels another to pay more than is legal or reasonable; one who is unreasonably strict in his demands or requirements.
4. One who exacts or demands by authority or right; hence, an extortioner; also, one unreasonably severe in injunctions or demands.
5. A person who makes illegal or unreasonable demands; an extortioner.