Earlier quoted context omitted.
If anything this, along with similar situation(s?) with Google, should stand as a strong warning against single sign on systems across multiple services with multiple TOS.
Why do you see this as a single sign-on issue? Seems to me the issue is over reliance on large SaaS providers. Same things happens all the time to Google users.
If the account is just for a cloud SaaS, then there's likely to be very few policies to disable your account.