There’s something odd about this story. Not naming companies is weird - this happened before GDPR which means it happened a minimum of nine years ago. There were no lawyers involved at any point, not even before signing amendments with a company known for punishing vendors on their way out. Nobody even seemed to mind that this shady company with such a bad reputation was reading client emails. There was no attempt to warn anybody or to even solve the problem.
I don’t believe that this ever happened. I don’t know why someone would make up a story like this but this one is very odd.