Tata Docomo — number showing as invalid

My tata docomo number is showing emergency calls only from past 2-3 days. I had it on my old phone until the past month and now it is the secondary sim for my new phone. I wasn't using that sim to call anyone since the past 6 months but i would receive messages everyday from the company. But now it says the number is invalid. This number is important for me so can you please resolve this asap.