Shotguns are made for windy dark nights. Callers don't always work, fox may have just eaten, or isn't interested in the sound, or you hit a wrong note and he doesn't like the sound of it.
Find their paths, where you know they like traveling. Wait on a good vantage point OFF the horizon and AWAY from village/town lights. The idea is to get your fox coming towards you. Where the dark windy night comes into play is you can then very quietly try to get closer. The wind should ideally be coming from the fox towards you, NEVER from you to the fox. The wind hides some but not all noise, I've ran