Heck, there was a high profile case up north a week or two ago where a man proved he was not the father but the court remanded him to continue child support payments because he has been paying them for so long already. Something like 11 years.
Usually what happens is if the man can prove he's not the father, he doesn't have to pay future child support but may still be liable for any arrearages, because he "slept on his rights."
That sounds familiar. I hope someone who was wrongly convicted doesn't draw that judge. The judge would tell him well, since you've already served 11 years, you might as well serve another 12 years.