I already registered for TCS. I got user ID and password in mail. But when logging both are mismatching.

Please contact their ILP support for getting your lost user number.

Here are the details for contacting them:

Toll Free No.:1800–209–3111

OR

You can mail them about your concern issue on : ilp.support@tcs.com

 Support service is from Monday to Friday- 8 AM to 8 PM.

Hope this helps you.

We're helpless here. TCS seems to have a very non-tolerant registration system. The only way to get help is to contact them and request to address the issue. 

By the way, did you try resetting your password? If your email ID is correct, you should be able to do that without any issues.