Not for profit password reset support

Hello. I was recently successful I setting up a Microsoft not for profit account for a community organisation I volunteer for. I have however had trouble logging in an asking for a password reset. I had been emailing the support team but they have not been replying to my emails as they said they couldnt verify my identity even though I provided them with everything they asked for. I am just trying to find out who I need to speak and what I need to do to reset the password as on the login screen there is no "reset password link" and the password I originally set doesn't work. Any help with this much appreciated as I am doing this voluntarily and what I thought would be a very simple request is turning out to be very time-consuming. Many thanks