There is a thread about these ad problems:
https://imcdb.kelcommunity.be/forum_topic-8103-70494-Testing_a_new_ad_company.html
the difficulty for tracking them is that usually it is just one ad that is concerned, and ads depend on the country amongst other criteria

see http://imcdb.org/temp/How_to_Find_and_Report_Bad_Ads.pdf for details on how to track info to include for reporting the ad so I can send that to the ad publishing company) + the address of the imcdb page on which you had the problem

if the page "locks" maybe you won't be able to get the required info though
in worse case, if you can't get the info and still have the problem, block ads for a few days, until other ads come instead of the problematic one