Sort by last name / first name is mandatory in Zoho Business

Sort by last name / first name is mandatory in Zoho Business

 Hi,
I'm at the beginning using Zoho Business. There are two issues I'm not very pleased with:

1. Sort by last name does not work. When selecting 'Sort By Name' the contacts are sorted only by the first name. Is there any option to switch to the last name?

2. The field 'First Name' is mandatory. imho this is not very sensible. I have lots of customers I do not know their first name, but always I know the last name. Is this a bug? Is there a useful solution or workaround? Entering a blank in the first name field lets zoho automaticly replace the blank by the email (the part in front of @).

Thanks for your help.

Thomas