How to activate Tata DOCOMO 3G in my Samsung Monte

I have a 3G mobile which is listed as compatible phone under tata docomo 3G services. I have a new 3G sim and i want to activate 3G. Also the videos are not playing in youtube. How do I do that. I have sent an sms to 53333 ACT 3G as per the advice of a customer care rep at docomo. but got no confirmation message. Please help me. Mobile model is Samsung Monte.Sandeep

from what i have seen tata docomo customer care is pretty useless wrt 3g services. i would advice you to try contacting them through facebook and twitter.