Although I was one of the few who got affected by this little accounting problem, I still really respect Dreamhost. Not only did the blog an apology and email me an apology, they even explained why this occurred and their solution to it. Honesty is the best policy.
I even learned something from them:
“The moral of this story is that “flexibility” is rarely desired in programming! The less a program will accept/the less a program will do/the less options and preferences it has, the more usable it is/the more understandable it is/the more stable it is.“
It’s too detailed to be made up, I guess. Anyway, my account is fixed and I’m still keeping my hosting with them.