Help replacing auto fill

[Geofee]

Hi all, today I noticed the auto-fill came/broke off, and I tried putting it back but with no luck.
So right now I shut off my water valve for the yard.
Does anyone know how to fix this? I am a very new ponder as I don't even know the set-up of this pond, it came with the house we recently bought
I am not sure if I just get a new one and get the old one off with plumbing pliers, or it's not that simple?
Any advice is much appreciated, thank you

PS: the blue tube in the picture at the bottom right is where the "floater" attached and also where the water comes in

 

[Big Lou]

Please provide a photo of the broken part.

 

[Geofee]

here are some close-up pictures
the first picture is where the water come in from
and the second picture is what it suppose to connect to, like the toilet valve
I tried to put it back in and put a pin in between to hold it in place, but the water continues to run

 

[Big Lou]

Thoroughly clean all parts. Examine the outlet to determine if it can be disassembled or removed from the supply pipe. Determine if the outlet and supply line is PVC. Look for a brand name and part numbers.

Now temporially attach the ball and rod using a twist tie or pin. Turn on the autofill water. Next physically lift the assembly upward to its max height. If the water continues to flow through the outlet that indicates the internal shutoff mechanism malfunctioned. You may be able to replace the entire auto fill device. You may want to contact a pond supply store that sells auto fill devices.