How do block unwanted phone calls from cell phone numbers on my landline?

I am not sure what you mean. You need to block calls to your land line from cell phones only? I don't think it's possible. You can call your phone company and ask them to block a particular phone number (for a fee), or you can buy one of those devices that let you block calls from 'unknown' numbers.

Another option is to find out who calls you and ask them to stop. You can enter the number that calls you at 800notes.com, http://800notes.com , to see if other people have reported calls from it. If yes, then you might find our who the caller is and how to stop the calls.