Each issue they raise can be challenged but they will not listen. A simple question to ask them is do they have any authority from the Quran to follow the hadith and sunnah of a man, Messenger, or not?
The words sunnah and hadith are exclusively used for the way of Allah and the sayings/ recitation of Allah, nothing else.
6:68 When you see them engaged in vain discourse about Our verses, turn away from them unless they engage in a different subject. If Satan ever makes you forget (your mind gets engrossed in their discourse,) then as soon as you recollect, no longer sit in the company of the people who confound the Truth with falsehood. [Zaalimeen = Those who relegate the Truth from its rightful place = In this verse, trying to displace or confound the Truth with falsehood]
7:185 Can they not see (and correlate what he tells them with) the Dominion of the heavens and the earth and what Allah has created? Does it ever occur to them that the end of their own life may be near (hence the time to make the right decisions is not unlimited)? What HADITH besides the Qur’an, are they going to believe after him?