1) In a protesting manner 
• (adv.) By way of protesting.
Pro·test'ing·ly adverb By way of protesting. 
[adv] - in a protesting manner
protestingly 1. In a protesting manner. 2. An expression or declaration of objection, disapproval, or dissent; often in opposition to something a person is powerless to prevent or to avoid.
adverb in a protesting manner; `the bed creaked protestingly when the fat man sat down`