Without knowing specifics it might be best if possible to just back away and let this die.

Person A took things way too far by stalking, bullying, lying to and having you ‘do things that hurt other people’. (Again, without knowing context but there isn’t much that could warrant such behavior).

They likely either aren’t as upset as they are making themselves to be and are using that to manipulate or are unable to process things in a non-toxic way. It’s a lose-lose situation as in both of those cases there is no reconciliation but it allows them to keep the narrative alive.

If the other people involved are people you are/were close with and you wish to repair, the best you can do is ask them to talk (in person or via message) so you can explain yourself. Then it’s up to them, that’s all you can do really. This is best done individually and I would recommend keeping Person A out of this as much as possible to avoid the perception of ‘defence by attack’.

In some cases there may be action to take to help repair the situation but as you’ve seen that can be a slippery slope, but as long as it’s not hurting anyone else it’s up to you how hard you want to try. I’m of the opinion that short-term actions mean little to nothing once some damage has been done and trust is earned back gradually not with a task list, but that’s just me.

Below is just a somewhat related personal story, feel free to ignore.

When I was young I got into a situation over my head at the time and hurt a friend dearly. I took my medicine and had it out with him directly 1 on 1 and apologized, we ‘settled’ it but it was not repairable IMO so I didn’t try. It did make its way to others in our friend group and I just tried to keep the topic as brief and surface-level as possible if it came up to avoid creating a buzz.

We were friendly after that but not friends, and I don’t blame him at all. It still bothers me but I did what I could after making the mistake and never expected things to go back.