Grounds For Child Support Post Emancipation In California

My ex-spouse is demanding that I continue to pay child support in CA even though I have paid above & beyond what the court had ordered in 2002. Are there grounds by which she can continue to get child even though both my sons have turned 18 and have graduated high school in CA? She has demanded that I furnish W2s for the past 4 years yet this was never required by the court order.
Please advise.