Not to bash your service, Ricky. But you should have known that for a business that's growing at such a pace, you would have clearly needed to expand your infrastructure rapidly.
You could argue that the surge of users was not exactly expected, but for a business such as your own, a 'reserve' stand by is almost ALWAYS necessary. And when I say stand by, I mean something that can be put into production usage with immediate effect, as opposed to time lags/delays. I would agree with others on the fact that you should have disabled payments (or at least delayed account activation with the reason you're providing here) while you're over loaded.
About no support on weekends. Well, yes, that is normally the case. But while you're overloaded, you should realize that you'll have more than the normal volume of queries. You should have, at least, some support staff (as well as techs, if possible) to cover these few weekends.
EDIT: With that said, I wish you guys at FileServe all the best. Keeping the few kinks aside that you've had these past few weeks, you guys have proved to be more promising than any other new filehost out there. Your features and speed of response (at least in this thread) as well as professionalism in handling queries all goes in your favor.