Water leaking into my wall, neighbour refuses access to their house , what can I do?

There’s water leaking into one of my house walls, and unfortunately my electrical box is on that wall, so I’m trying to get it fixed as soon as possible.

I’ve already contacted a few contractors to trace the source of the leak. They checked my roof and patched areas on both my house and my neighbour’s side of the wall. I even paid for the repairs on my neighbour’s side because I didn’t want to trouble them. I also informed them about the situation, but they didn’t seem very concerned.

On my side of the wall there are no water pipes, but my neighbour has a bathroom directly on the other side. My contractor suspects the leak might be coming from a damaged pipe in their bathroom, but we can’t confirm without checking.

The problem is my neighbour refuses to let my contractor enter their house. They insisted on calling their own contractor instead, which is fair. But their contractor apparently checked and said nothing was wrong, which I’m honestly a bit doubtful about.

Can city council help on this? or they don't? Need some advice...