“Technically, an aguna is a woman who’s husband disappeared, NOT one refused a get. “
An agunah is any woman who is prevented from remarrying, whether because her husband disappeared deliberately or againt his will, or if he refuses to give her a Get. She is chained to a marriage with no way out. I know a woman whose rabbonim, after unsuccessfully making several attempts to encourage her recalcitrant husband (who was trying to extort money from her family) to give her the Get after many years that they no longer lived together, finally told the husband that unless he gives it to her immediately, they will collectively daven for her to be kosher to marry a kohein on such and such a day the next week. She was called to a Beis Din to receive her Get within 48 hours.