Has anyone looked into their terms and conditions? Usually any resulting damage from software malfunctioning is excluded. Only the software itself being unavailable may be an SLA breach.

Typically there would also be some clauses where CS is the only one that is allowed to determine an SLA breach, SLA breaches only result in future licence credits no cash, and if you disagree it's limited to mandatory arbitration...

The biggest impact is probably only their reputation taking a huge hit. Loosing some customers over this and making it harder to win future business.