Charles Ellicott Commentary Judges 11:28

"Howbeit the king of the children of Ammon hearkened not unto the words of Jephthah which he sent him." — Judges 11:28 (ASV)

Did not listen. —We are not told of any counter-arguments. Probably the king of Ammon cared only for the argument of the sword—

“The good old rule
Contented him, the simple plan
That they should get who have the power,
And they should keep who can.”