collect on (something)
To request or pursue something that has been offered or promised to one. Remember when you offered to watch the baby? Well, I need to collect on that now. It's time to collect on that debt he owes me.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
collect on something
to take or receive payment on a debt or promise. I have come to collect on your debt. I will have to assign your account to an agency to collect on this bill.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.