My Mobile went crazy for few day

Today one of my friend got angry to me.
the reason is why i didn't answer the phone or the mail.
but actually i didn't get the phone nor mail.

What is the deal????

the problem is that my mobile went crazy for a while.
for sure, even my friend make a call in front of me,
my mobile still don't show any income call.

then after i realize the abnormal case,
i just restart my mobile.
then,what a surprise!
i got many miss calls and mails.
and the date was 19th.

so it mean my mobile went crazy since 19th December.
ohh my good.
sorry to those who ring me or mail me on that dead period.