Some mattresses have a power fail alarm is this goes off try to join the pipes together from the pump or put the mattress in transport mode (nimbus3)

Check the emergency stop button as not been pressed in you can check this by turning it,
It could be the handset you can override the handset by using the emergency raise and lower on most of the hoists you can do this with a pen tip in 2 small holes below the stop button.

There is nothing you can do if you have checked all pipes from the pump to mattress or ok.
You must try to get them off ASAP or use 24hr call

The catch must be broken, try to put that side next to a wall if possible

This is normal with this type of mattress , most pressure relieving air mattress go through a 10 min cycle when all the odd cells go soft then all the even cells go soft, when there is cells soft next to each you must get it repaired .

On the actuator, the part that raisers and lowers the hoist there is a emergency lower on that you must pull that up. If it still does not lower get someone else to push down on the boom at the same time it should then go down.

If it was delivered by ACS Healthcare you will have!!