Problems with My Stuff

Firstly, I’m not tech savvy enough to know what version of WP we’re using.
Issue – I rather foolishly made a private comment about an issue I had in the past (not related to my group). There are other members of the group that can view this, I only just realised, in ‘My Stuff’. I’ve tried to wipe the comment away (can’t), and have asked the recipient to delete the comment (don’t know if that will help) He hasn’t responded so far, hopefully he will.
I just don’t want the other group members to see private business from my past. I didn’t realise it would show private comments like this or that it would link back to the shared site. Can anyone help?

https://wordpress.org/plugins/my-stuff/