Tata Docomo — number always busy

Whenever any one call me it showing busy. I am unable to receive a cll nor sms please solve my problem. I contacted customer service but they were also no t able to solve it. My no. Is [protected]. I am i have tried all usss codes. Right now i am in poland and my cellphone is catching full signals and i have balance too available in my no. Can you please sopve it.