Laundry washing machine doesn't keeps water

Sounds like the machine is stuck in the drain cycle..you can try a couple of things.Switch off from mains...

Look at the bottom at the front of the machine and locate the "pennytrap" this is usually a cap that screws on but put a towel on the floor and a small bowl to collect any surplus water as you unscrew this cap...sometimes the pipe can be pulled out to help drain into a bowl....now look inside and retrieve any buttons or coins that may have gotten stuck.Replace cap and just put machine into a quick cycle rinse and spin.if it stills refuses to fill then it could be the pressure switch.this is basically a pipe that leads from the pump to the drum.this is usually full of air and works when the drum fills causing the air pressure inside the tube to build up and trip the switch off...thus shutting the fill cycle off ..you need to disconnect the pipe and drain out any fluid so that there is only air inside the tube and reconnect....then quick rinse and spin to see if that cures it....as a last resort tap the drain pump with a wooden hammer just enough to dislodge the impeller which could be stuck open thereby causing the machine to continually drain without filling.