Why wont it let me change my name?

Ive tried to change my name on Snapchat to my full name but it wont let me. Ive changed it three times, restarted the app, asked and checked my friends phone to see if my user name change. It didnt and its upsetting. Please fix it, I really love this App.

L͟o͟l͟l͟i͟t͟a͟ V͟i͟o͟l͟e͟t͟ about Snapchat, v10.4.1.0