1. I created an online case form including the first name, last name and company name
2. using the external link provided, I suggest my clients to enter the case such as what I am doing right now on Netsuite
3. the client logs his case; we even pre-populate those fields from the info we have on them when they are logged in

Result:
the case is logged; the client receives an email confirming that it has been received; however the case is not associated with the client itself and the contact, meaning that the system did not recognise the email of that person as being already a contact in the system, and instead associated the case to "Anonymous Customer"