This forum is for the BraveMailer service. It seems that you are asking a question about your Bravehost or Bravesites email.
We do have some spam prevention, however in order not to trap any legitimate mail for our members this does have limitations. We also subscribe to multiple RBLs (Realtime Blackhole Lists) which will list sources of spam which we automatically block.
We suggest reporting these to SpamCop, which notifies all companies in connection to the email (email provider, host of any sites in the email, etc) and requires them to take action to stop the spam. Failure for online providers to do so can result in being listed on RBLs as mentioned above.