collecting receipts 

taking screenshots/pictures/video/any form of footage or audio to be used against someone. like when an lawyer provides evidence in court.

"Girl, I was collecting receipts on what's going on between her and Bob."
"Oooooh, I want to see!"

collecting receipts by nerdykpopfangirlgamer November 8, 2017

Collecting the Receipts 

(v) the act in which one screenshots text conversations to use as blackmail in the future

Susan: I can’t beileve he said that? He shouldn’t get away with that

Clair: Girl he won’t. I’m collecting the receipts.

Collecting the Receipts by Claret Mcbrowb June 12, 2018