Of course I did, but it had nothing to do with the issue. 

In fact, I strongly believe that it should be possible to prevent anyone from becoming your representative, not only after your CRA account is compromised. Or, better yet, the CRA should enable you to create a special password which you would have to give to anyone whom you're going to authorize to access your CRA account. That would be a simple, yet very effective solution to prevent unauthorized individuals from accessing you CRA account. The CRA should have thought about that long ago; alas, the words "government" and "thinking" are often miles apart.