Since you can only call Xbox Live support to cancel your account I did so and spoke to one of their support representatives. He accidentally cancelled both my Xbox Live Gold account and the PSU Guardian's License...

So be careful when canceling, and be extremely clear that they understand you only want your PSU Guardian's License canceled. Now I have to wait for them to reissue me a new code to reactivate my Gold account, which they said would be 3-5 business days...