If I register a domain name with DiaMatrix must I have my hosting with you as well?
Please note that a domain is nothing more than an 'address' that the browsers on the internet use to locate your website and emails, etc. Should you want to setup your website or emails on your domain, you will need to take out a Hosting Package (i.e. space on a server) which is linked to your domain.
Therefore, you do not need to host your domain with domains.co.za even though you have registered your domain with us. Domains.co.za does offer free DNS hosting which allows you to point your domain to a different ISP (hosting provider - not URL) should you choose to do so.