All email to gulftel being bounced with error 550

All email to gulftel being bounced with error 550

Hello

Firstly I have sent 2 messages to support using the contact form and I have had no acknowledgement.

From this morning all my personal mail to gulftel.com is being bounced and from reading the message from mailer-daemon@mail.zoho.com gives error code 550 on reading the spamhause link it is mentioning PayPal and that does not make sense as I don't have a PayPal account.

What has made me most annoyed is Zoho has not acknowledged my emails which I marked 'critical'.

I pay Zoho to host my domain “Merciadragon.net” and in the last 5 years I have had nothing like this. If necessary I will move my domain.

Below id an edited mailer-daemon@mail.zoho.com message.

Robert….

This message was created automatically by mail delivery software.

 A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. 

xxxxx@gulftel.com, ERROR_CODE :550, ERROR_CODE :5.7.1 [C11] SBL-XBL Restriction:  See https://www.spamhaus.org/sbl/query/SBL293648


 Received:from [192.168.2.170] (cpc15-hink4-2-0-cust200.8-2.cable.virginm.net [86.0.158.xxx]) by mx.zohomail.com
        with SMTPS id 1460222526802882.2619759025721; Sat, 9 Apr 2016 10:22:06 -0700 (PDT)
 Message-ID:<57093A3B.2030303@merciadragon.net>
 Date:Sat, 9 Apr 2016 18:22:03 +0100
 From:Robert Fletcher <robert@merciadragon.net>
 User-Agent:Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.6.0
 To:Jack & Pat Hughes <xxxxx@gulftel.com>
 Subject:Re: I think I have it
 Content-Type:text/plain; charset=utf-8; format=flowed