One of the most complained about domain renewal scams comes from a company called "Domain Renewal Group". This company scours your details from domain registrars (which by default is publicly available) and produces a renewal notice. The renewal notice is sent out in hardcopy (ie not an email) and looks like a renewal form. This company isn't the original registrar of your domain and they're relying on the letter to look deceptively like it is. Do not pay this, their business relies on people not reading the form in it's entireity (especially the fineprint).
Here's a copy of what the scam email looks like:
Conetix suggests that you read all correspondence from domain renewal companies very carefully, especially when they're not from an Australian company.
Please feel free to forward your corresponence through to Conetix if you believe it's a scam and one of our support staff will help evaluate it for you.