Can a "copy-and-paste" haphazard non-compete be legal?

Last November, my ex-employer got to a point where he threatened me, after over a year of verbal abuse, harrassment, suspicious discrimination and general mistreatment. When I complained to HR, they started a third-party investigation, and when it concluded my boss called me and apologized for an hour. No other steps were taken. Needless to say, I found another job soon after, and finally after repeated requests got a copy of the non-compete.
I joined my new employer shortly thereafer, and have done my best to comply with the non-compete, although I do still work in the same field. I have not pursued any of my previous employers' clients, and our business focus is very different than theirs (I work in shipping, and we handle other type commodities, from other origins) and although we have an office close by, I work mostly out of my home, in another county.

My question: a recent new client was referred to me by a client I obtained, and once we got close to closing business, I found out he had worked with my previous employer. I can still pull out, but the previous employer called to advise he's pursuing the matter.

Will my previous situation with this employer invalidate the non-compete? I can still press charges, seeing the outcome of the investigation. They also did not pay severance to keep me from seeking employment in the same field, and this new client did not come to me by my active pursuit. I called thousands of business leads while at my previous job, and cannot recall every person I spoke with, nor be expected to, but I have acted in good faith always.

One more thing and in reference to my question, I had the non-compete looked at by an HR professional, he said it was haphazard, copied-and-pasted, and would have no bearing. My ex-employer is well known in our trade to play by his own rules, and has had legal issues before.