My Magic keyboard isn’t working despite hard shutdown

I just need an answer to this. For some reason, the iMac suddenly restarted out of nowhere and I logged back in. However, the keyboard and mouse froze after that. I did a hard shutdown (before this the keyboard worked again) and the mouse worked but not the keyboard, despite restarting over and over. I can’t log in to my iMac now because of this. Due to this I am unable to give out iMac info. I also had the keyboard charged before this issue started.