Filtering out email by sender can be complicated, what at first looks like a simple process of adding the senders From address in the filter can actually be far more complicated. 


Here is a real world example:


Received: from pmta1.delivery7.ore.mailhop.org (54.186.27.61) by
CLU-EXCH.customer.local (10.0.25.213) with Microsoft SMTP Server id 14.3.174.1;
Mon, 18 May 2015 15:18:30 -0600
Received: from customer.com (unknown [104.219.12.197]) by
inbound5.ore.mailhop.org (Halon Mail Gateway) with ESMTPS for
leads@customer.com; Mon, 18 May 2015 21:15:43 +0000 (UTC)
Received: from customer by server1.sleekhost.ca with local (Exim 4.85)
(envelope-from clazyuco@server1.sleekhost.ca) id 1YuSNx-0001qw-Qf for
leads@customer.com; Mon, 18 May 2015 17:15:41 -0400
To: leads@customer.com
Subject: *SPAM* Request to plan your stay
X-PHP-Script: www.customer.com/index.php for 70.59.7.26, 70.59.7.26
Date: Mon, 18 May 2015 21:15:41 +0000
From: C Lazy U Website - customerwebforms@gmail.com
Message-ID: e0b8e143d7434794e64067a148de10d0@www.customer.com
er-Via: server1.sleekhost.ca: authenticated_id: customer/only user confirmed/virtual account not confirmed

(/e0b8e143d7434794e64067a148de10d0@www.customer.com)leads@customer.com


The important part to look at here is even though the From: C Lazy U Website - customerwebforms@gmail.com indicates one thing, the headers say something completely different. 


(envelope-from clazyuco@server1.sleekhost.ca) id 1YuSNx-0001qw-Qf for leads@customer.com; 


The correct address to filter is the envelope-from ID if filtering the From address does not work.  


If you have problems getting your filters to work, contact customer care and they can help you refine your filtering rules.