Another problem you may also have - If you have an electric handbrake then it might need to be calibrated using Citroen diagnostic equipment, unless your friend has already done this.
Whilst being worked on, was the battery disconnected to stop the suspension moving ? If so it might help to do a battery disconnection/reconnection. There is a procedure in the C5 Technical Section Common problems topic.
Sometimes this can self correct if left or the car used a bit but some simple things to check:
- as noted above, can you hear the pump running ?
- if you open and close all the doors does this cause the pump to run ?
- you could try bouncing the car up and down.
- have you checked the LDS tank fluid level with the suspension on low level - the fluid should be just covering the bottom of the strainer in the tank.
- has the LDS tank split and leaked fluid since this can happen if the car is jacked up without first raising the suspension and slackening the tank cap to release any pressure. The cap should not be tightened until the car is back on the ground.
- have you checked if the pump fuse has blown. It is a maxi fuse in a small fusebox near the side of the battery. It might have a red cover.
- you could try jacking the car back up, use axle stands, disconnect the battery and then see if the height sensors have been damaged. You could also move the sensor arms to see if they are seized or even broken (common problem and new arms are available at little cost from Citroen).
- whilst jacked up see if the wheels/suspension can be moved.
Failing this you might need a trip to a Citroen dealer but I seem to remember a topic where a car's suspension corrected itself whilst going over bumps to a dealer. You might need to go there anyway to have the handbrake calibrated if it is electric.