This is a confusing discussion!
Yesterday, I wished I had not said the things I said last week.
Today, I wish I did not say what I said yesterday.
Today, I wish I had not said what I said yesterday.
You know, I am not sure! It seems like it should be this way:
I wish I did not say that.
But if I was speaking I would say:
I wish I hadn't said that.
That is what I think is best, but I am not sure!