search contacts by phone number, filter using a 3 digit prefix -

i want phone numbers in contacts start specific 3 digits, eg "012" when hit button.

i've been working on using following code:

private void buttoncontacts_click(object sender, routedeventargs e) {     contacts cons = new contacts();     //identify method runs after asynchronous search completes.    cons.searchcompleted += new eventhandler<contactssearcheventargs>(contacts_searchcompleted);     //start asynchronous search.    cons.searchasync("0109", filterkind.phonenumber, "state string 5"); }   void contacts_searchcompleted(object sender, contactssearcheventargs e) {     try     {         //bind results user interface.         contactresultsdata.datacontext = e.results;     }     catch (system.exception)     {         //no results     }      if (contactresultsdata.items.any())     {         contactresultslabel.text = "results";     }     else     {         contactresultslabel.text = "no results";     } } 

but filterkind.phonenumber works when has @ least last 6 digits matched of phone number.
idea how achieve this?
btw i'm total beginner.

as say, filter of contacts api match if last 6 digits same, can see in documentation, can't using it.

in opinion best way receive contact list , after use linq find contact want.

private void buttonbase_onclick(object sender, routedeventargs e) {     var contacts = new contacts();     contacts.searchcompleted += contacts_searchcompleted;     contacts.searchasync(null, filterkind.none, null); }  void contacts_searchcompleted(object sender, contactssearcheventargs e) {     var results = e.results.toarray();     var mycontacts = results.where(c => c.phonenumbers.any(p => p.phonenumber.startswith("66"))).toarray(); } 

you can see in last line query find contacts of numbers start 66. can change query want match numbers want.