If you don't want your number to be in the Simpler Contacts app database, then enter your phone number below including the country code and press 'Opt out'. 

This mechanism allows you to opt out from sharing information related to your contacts which you may have shared with us.
You may choose to opt out all contacts or your specific contacts. You may opt out (Contacts) at any time through, just navigate to Settings -> Account and switch off the sharing option.

Opt out phone number

Opt out address book