You need to go to the nearest telekom and tell that you want to terminate your streamyx as well as your old house number. You will also be required to pay any outstanding amount on it, that is if there is any outstanding to begin with. Remember to bring a photocopy of your IC if it's registered under your name.

Well you should have expected is from TM. They won't be courteous enough to do most things for you . As for converting, Unifi is a totally new account while Streamyx is another so i guess it's impossible to do any conversion since the bill itself is different :|