What is the ruling on insulting a religious man, knowing that the insult was not because of his religiosity?

You have wronged by reviling this religious man who has a great right over you. Reviling a Muslim is generally forbidden, and you must repent from it. The reason you mentioned for reviling him is unacceptable neither religiously nor customarily. He is not obligated to offer you a service; rather, it is you who should offer him services.