This happened with me too. I had easyshop platinum. Applied for upgrade to Millennia. Did not receive any sms/email confirmation, so thought it didn't work and applied for upgrade again. Now I have two millennia and platinum linked to the same account. Since I have more than 1 account need to see if they can change the primary linked account on the second millennia. Netbanking shows option to link account but doesn't seem like it will change the primary account. I don't have clue how the linking feature works though.
Update: They deactivated the second millennia. So now I have just one millennia for the primary account instead of two.