Get Attributes from Amazon Connect to Amazon Lex

Hi,

I have in my contact flow this:
Stored Customer Input ---> Set contact attributes: Key: numberInput, Type: System, Attribute: Stored customer input ---> play prompt ---> Get Customer Input: With my Lex's BOT

and in the lambda of my Lex's BOT
var phone = event.Details.ContactData.Attributes.numberInputs;

but when I try to get the customer's number I got nothing.

what Im doing wrong? what Im missing?