+ When a broadcast channel or scheduled channel is being created, the total cost must be calculated for the campaign and it must check against the available balance in the customer’s account so that the broadcast channel or especially scheduled channel doesn’t fail. The same must also be checked for drip campaigns. Probably a setting for the user to set a minimum amount for low balance can also be introduced. Besides that, the campaign must also check the opted-out contacts / blocked contacts during the calculation process.