email attachment loop wrong

@InvocableMethod
    public static void sendEmail(List<String> invoiceID) 
    {
        string emailAddresses;
        List<International_Invoice__c> invoices = [SELECT Id, Freight_Forwarder_Email__c FROM International_Invoice__c WHERE Id in :invoiceID];
		List<Messaging.SingleEmailMessage> mails = new List<Messaging.SingleEmailMessage> ();  
        List < Messaging.EmailFileAttachment > attachments = new List < Messaging.EmailFileAttachment > ();
        List<Id> attIds = new List<Id>();
        for (International_Invoice__c invoice : invoices) {
        emailAddresses =  'ben.p@test.com';
        Messaging.SingleEmailMessage message = new Messaging.SingleEmailMessage();
        message.setToAddresses(new String[]{emailAddresses});
        message.setSubject('subject');
        message.setHtmlBody('body' );  // If the body is empty, use an empty string
        // Don't set the reply to, because it's auto-calculated.
        message.setUseSignature(true);
        message.setSaveAsActivity(true);
            for(Attachment att: [select id,body,parentId,contentType,Name from Attachment where parentId =: invoice.Id])
            {
                Messaging.EmailFileAttachment attach = new Messaging.EmailFileAttachment();
                attach.setContentType(att.ContentType);
                attach.setFileName(att.Name);
                attach.setBody(att.body);
                attachments.add(attach);
                attIds.add(att.id);
            }
        message.setFileAttachments(attachments);
                mails.add(message);
        }
        Messaging.sendEmail(mails);
    }