Tata Docomo — upc code not generated

I'm having tata docomo sim which is active on airtel network. I tried getting my upc code by sending a message to trai on 1900. But i got no response from 1900. I have treid a number of times but still am unable to get my upc code. My tata docomo number is [protected]. It's important for me to get the upc code as it is also linked with other details and i want to go to other networks. Please help.