If a foreign state actor gets someone illegally elected in a separate country with dirty money, this is not an "accounting issue".
(later edit: Actually probably they did not pocket the ad money, since I think the accusation is most of it was not legitimate ads, but puppet-account posts from some service. Of course, TikTok could still be be held responsible to better police these, but perhaps is not the direct destination of the money.)
Also what can they do besides disqualifying him or delaying the elections for months(years?) until he's convicted of fraud (hopefully by that point all of his voters would have forgotten all those ads)?