Hyperbole

The expression is adverbial, but it's comprised of a preposition and a noun. Still no verb in sight.

Best you write to them and set them straight then eh?

Oh, and everyone else:

**ad nauseam **

 Also found in: [Medical](http://medical-dictionary.thefreedictionary.com/ad+nauseam), [Idioms](http://idioms.thefreedictionary.com/ad+nauseam), [Wikipedia](http://encyclopedia.thefreedictionary.com/ad+nauseam), [Hutchinson](http://encyclopedia.farlex.com/ad+nauseam)  0.03 sec.  div.Ov { width: 550px; }   ad nau·se·am  (![](http://img.tfd.com/hm/GIF/abreve.gif)d nô![](http://img.tfd.com/hm/GIF/prime.gif)z![](http://img.tfd.com/hm/GIF/emacr.gif)-![](http://img.tfd.com/hm/GIF/schwa.gif)m)*adv.* To a disgusting or ridiculous degree; to the point of nausea.

[Latin ad, to + nauseam, accusative of nausea, sickness.]
The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
ad nauseam [æd ˈnɔːzɪˌæm -sɪ-]adv to a disgusting extent[Latin: to (the point of) nausea]

Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003
ThesaurusLegend: Synonyms Related Words Antonyms
Adv.1.ad nauseam - to a sickening extent; "he played the song ad nauseam"Based on WordNet 3.0, Farlex clipart collection. © 2003-2008 Princeton University, Farlex Inc.
ad nauseamadverb (Latin) again and again, over and over (again), on and on, time and (time) again, time after time, ad infinitum, times without number We discussed it ad nauseum.
Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002