Hello varad.
As you are saying that it is showing you already registered then you will have registered for MCC in first attempt may be now you are forgetting the details.
You need not to worry about it much just check for forget login id and password. May be it will. Helpful for you. In case not then you can simply visit site if MCC there you will find a lot of helpline number to assist you better.
Ok
Good luck don't worry..