A blocklist enables you to ensure your team don't call leads that do not want to be contacted. This is done by using 2 simple features, blocklist & automatic deduplication.
Create a list with leads that do not want to be contacted or you shouldn't contact for any reason. Next:
Go to the List Configuration section for that specific list.
Under Settings, select Blocklist tick box
Using the Blocklist
Whenever you upload new leads within Myphoner you can use the automatic deduplication feature to remove the leads that are in the blocklist. To do that:
Go to Manage > Duplicates > Dedupe
Select the list(s) you want to dedupe.
Under Dedupe Strategy select Dedupe leads matching Blocklist leads.
Decide which Dedupe Method to use (delete will generally work with this process).
For a detailed overview of bulk deduplication check out the full article