Last we saw, the Iron Bank was calling in part of the debt owed to them by the crown, and Cersei admitted they couldn't afford it. Surely the bank will be following up soon — they aren't ones to let a debt go unpaid for long.

In the book, it's made clear that the Iron Bank will eventually start funding the enemies of a delinquent borrower in order to put pressure on them to pay up. Cersei might be reaping even more enemies in season seven by ignoring the crown's debt.