I have a strange problem.I cannot call a specific mobile number from my mobile.This mobile number is new series number, network operator is TATA Docomo Pune.I tried to change the handset (from N85 to W800) but still of no avail.The error is "This is not a valid number."Weird thing is that I can call this number in roaming (other state).I complained Airtel and they got back and said that its my handset problem. When I told them that I checked with other handset too, the call was disconnected. Tried to explain the next customer care agent, but still of no avail.What should I do. Is it service provider issue?ps: I have checked with my friend, he confirmed that my number is not blocked in his mobile.