A small exchange doesn't need an automated system to deal with tx mutability. We don't. That is because 99.9%+ of the tx will never be mutated.
We'll see who sinks and floats as other exchanges pick up the slack and grow.
I wish you and them all well, but I would be surprised if there aren't other noteworthy casualties.
Damn, looks like it happened
http://www.coindesk.com/massive-concerted-attack-launched-bitcoin-exchanges/MtGox was just the first (and biggest) victim. And the wallet is vulnerable due to bugs as well
https://bitcoinfoundation.org/blog/?p=422Looks like the devs and foundation finally decided to step on it and work together. Which is great.
As an aside, bitcoin is technology, not religion, it's not about what's right or wrong or who is to blame.
Technology is about moving forward, fixing bugs and delivering, once you get entrenched in finger pointing, you're losing the plot.