Hacked Site – random messages going to subscribers

My site was recently hacked – it’s still be sorted through – however – a number of subscribers have forwarded to me emails that they are receiving from this plug-in, asking them to confirm their subscriptions. It actually says ‘you have requested to manage your subscriptions to the articles on *****. Follow this link to access your personal page’ – can you tell me why subscribers are receiving this email and do you think it is related to the hack?

https://wordpress.org/plugins/subscribe-to-comments-reloaded/