I told you so
I warned you in advance, especially of a bad outcome. For example, It's too bad your guests didn't get along with each other, but remember, I told you so.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
Examples from the Web for i told you so
“Surely,” was the response, delivered in an “I-told-you-so” tone.Dorothy's Triumph
At the best, most of his friends proved to be of the I-told-you-so variety.The Mission of Janice Day
Helen Beecher Long
He had adopted an I-told-you-so attitude that grated Crag's nerves raw.First on the Moon
"This is the road I told you of," explained Sally with an "I-told-you-so" expression.The Slipper Point Mystery
Augusta Huiell Seaman
Of all this, however, the object of their "I-told-you-so" was serenely ignorant.Satan Sanderson
Hallie Erminie Rives