getting calls — getting calls from unknown number

Address:

Rajasthan

Today ,22nd SEPTEMBER 2011, I Receieved A Call From [protected]. I Didn’t Noticed The Country Code And I Have Try To Call It Back And Then I Realize It Was Not India Number And I Ended The Call In 4 Seconds. It Came To My Knowledge That Call Is From Pakistan. However,I Am Concerned About How Did The Calling Person Got My Number. I Would Appreciate It If You Would Look Into This Matter.