As we have checked the number assigned to Natinee is +6621050430, the other number +6621050421 is assigned to Suda Borisuthswad. I have checked on Active Directory only one number 6621050430 is assigned to Natinee, please refer the screen shot attached.
Also, I have checked on Natinee’s Lync properties at my end its showing only one number +6621050430. I will suggest you to update your outlook contacts and after that you can see only one Lync Number for Natinee.