Extra rubbish in the bin?

Set up surveillance and work out who the culprit is. Get someone to roll the bin out with you in it instead of any rubbish. When they lift the lid, you will know who it is. Then tell them you don't mind them putting some extra rubbish in your bin, so long as it is not too full because that results in your bin not being emptied. Good luck.

Have you spoken to your neighbour about this? If your neighbour is not the approachable type, maybe put a notice on the bin asking for it not to be overfilled. I've been closing a gate that belongs to a church close to my house that opens out onto the pavement for the past 8 years.My husband at last put a notice on it recently politely asking people to close the gate, so far it's worked.

Edit:Virgil, are you able to just leave black bin bags out for collection rather than a bin?

We have the same type of collections and neighbors who run out of space in thier bins and borrow room from us. We keep it in the garage now and empty smaller barrels in it the morning of garbage pick up. What a pain.

Tell them to stop putting their rubbish in your bin or you will dump it on their doorstep.

find a way to lock it up