Is it possible to ban users from bidding?

Yes. If you add a user to the website’s blacklist, then they will be logged out immediately and prevented from logging back in. 

The registration process flags newly registered users who are suspected of being on your website’s blacklist and notifies administrators. Administrators can see a list of all IP addresses used by a particular user, along with a list of other accounts that have used the same IP address.

You can also keep administrative notes for each user.