Unban IPs

Hi,
I’ve been asked to manage a site I’ve never worked on before.
Here there is you plugin.
People in the company gets banned fot multiple attending a valid login (they say the page gets a sort of timeout so they login againe).
I’ve got only access to wp backoffice and ftp, nothing else.
I’ve tried to deactivate the plugin but people still stay banned.
My two question:
1. how can I manually unban people
2. how can I deactivate permanently your plugin and its action (since I’m not able to manage i’d like to use something easyer via daskboard)
Thanks a lot for your help