Since today morning im not able to contact my friends under 18 yrs of age.what has happened? Do you guys have same problem?

Since today morning I'm not able to contact my teen friends who are less than 18 yrs of age or less. Some were my best friends. Even I searched for other person with same age but I can't see their profile .
There were so many my sweet little friends.
What happened ? I can't understand the problem.
Does this problem is faced by you guys also?