The entire business model of a SB or CFD provider depends on continuously and accurately hedging their risk exposure, and I am sure the regulator demands they keep this working. I would be more than surprised to hear that they had suddenly failed to do this and effectively had to close their doors to existing clients.They probably don't hedge their spread bet and CFD poisons. If I was not able to benefit or cut my loss on time due to their fault I do have a case. They did not answer their call.
What else was going on with your account at the time?