When a user suspects that they are the victim of serial voting, they should contact the site moderators with a custom flag which clearly explains what they think is going on (after 24 hours have passed, to allow for system to reverse the votes). While the CM team can be contacted directly using the "Contact us" form, this is generally not the preferred option, for a number of reasons.
This guidance is covered in many places on Meta Stack Exchange.
If the 24 hours has already passed and the suspicious votes have not been reversed, you can then flag one of your own posts and explain what happened so a moderator can look into it.
If after 24 hours (give the script time to run) you still see a problem, then raise an "in need of moderator intervention" flag on one of your own posts and ask a moderator to look into the anomalous voting patterns. Be specific as to what you feel the issue is.
... If it still hasn't been corrected, contact the SE team via the "contact us" link at the bottom of any page on the site. Using this method is no faster than raising a moderator flag. In fact, people have reported that it tends to take longer.
This is a problem for the mods to handle. Flag either account (the suspected serial voting account or the suspected target account) for the site moderators' attention.
... Using the Contact Us form will also work, but is overkill and less quick.
There are many more examples of similar posts on Meta Stack Exchange, as well as per site Metas, and as far as I can tell, they all consistently say that site moderators should be contacted first, and several don't even mention contacting the CM team.
On the other hand, the resource that is looked at by a majority of users is the Help Center, specifically the Help page on serial voting, and the guidance on that page is completely the opposite of the guidance on Meta:
What if I think I'm the victim of voting abuse?
If you see very unusual votes being targeted at your account, don't worry about it. You should wait at least 24 hours after noticing before becoming concerned, as the automated system should detect it and reverse it for you. If, after 24 hours, you do not see any fix to your reputation, please contact the team using the "contact us" form located at the bottom of any page.
This page says nothing whatsoever about contacting the moderators via a flag, much less that it's the preferred option to contacting the CM team. This appears to be an oversight, so unless I'm missing something, I think the wording in this Help page should be changed.
Site moderators have the ability to edit some of the pages in the Help Center for that site, and if this page is one of them, this might be the appropriate thing to do, especially if the guidance should be different on different sites across the network. But if the guidance is meant to be the same across the network, then I think all the Help center's pages should be updated in concert.