Boiler: Glow-worm 24C- Low water pressure, no heating/hot water ?

I have a Glow-worm 24c boiler, and since last night its not been working. One of the lights is flashing red, the one with 60 above it, and 'bar' below it. (It has a symbol of an upside down triangle.)
And the pressure meter is on 0, in the red.

The gas is working, but we have no hot water and no heating. Can you tell me how to fix this?
I'm sure its a problem with low water pressure, but the maintenance people I have to call to fix this are useless and not helping me at all.

Thankyou