Chargeback prevention alerts are a dispute resolution tool.
If the issuer is a member of either the Ethoca or Verifi alert network, the issuer will send a prevention alert to notify the merchant in real time of a transaction dispute. The merchant can respond to the prevention alert by refunding the transaction in question. This should stop the dispute process and allow the merchant to avoid a chargeback.
More information about chargeback prevention alerts can be found here.