dun for
dun (someone) for (something)
To nag or bother someone to pay money owed. Don't answer the phone—creditors keep dunning me for money that I just don't have right now.
See also: dun
dun someone for something
to harass someone to pay a bill or deliver something. If you don't pay the bill, they will dun you for it day and night. My job is to dun people for payment of their bills.
See also: dun