This does not bode well, and it would seem that the company may well be in trouble. However, best not jump to that conclusion just yet.
Have you tried telephoning them? If you do, make sure you take down details of who you spoke to and the time together with brief details of the conversation.
If this fails to get a response then you will just have to take it on the chin and fix the PC yourself. You say that the power supply has stopped working? I take it you have tried the obvious such as the fuse etc? If this does not help then a new PSU will set you back £20-30 for a half decent one and they are quite easy to fit.