my toilet systern is not filling with water when flushed. im having to manually fill the systern with water to get a flush

This is normally a problem with the cistern filling valve, debris in the pipe such as solder etc can block up the hole in the cone inside the filling valve which therefore will not let any water or very little water through to fill the cistern. If this is the case you can easily rectify this problem by unscrewing the filling valve to expose the cone and giving it a clean. Just make sure the water feed to the cistern is isolated before undertaking this task otherwise you will need a mop and bucket. Hope this helps.

Have you checked that the float is operational, does water enter cistern if you push down on the float? it sounds as though you may need a new float valve in the cistern

Your ball valve is more than likely blocked. If it is old the washer can sometimes stick or dirt and grit can get lodged at the outlet preventing water from getting through. this is especially common if your water has recently been turned off. At worst you will need a new ballvalve. A good plumber will do this in about half an hour. Hope this helps.

Could be a blockage in the ballvalve ,not a difficult or costly job to do

The inlet valve has more than likely become blocked. It should be able to be removed and cleaned out but often replacement of the valve is the better option.