SKYPE for BUSINESS - remove / block user

Hello, in company we use Skype for Business 2016. Unfortunately I have one stalker colleague, so I want to forbid that person see my status but to have possibility to write me.

That person add me into favourites also. I dont add him into favourites.

What will happen if I choose decline the request?

What is the difference between block that person and remove from contact list?

Or is there possibility to make my status visible based on groups like friends, colleagues.....or based on relationships?