Active job

Drainage problem

My house is on a sloping section with two houses, mine is the bottom house. The house above me has been doing excavations and it seems a lot of run off from the clay they have dug up has created a pool of mud around one side of the exterior of my house. I need some advice on if this has been caused by the neighbours excavations and if there is a way to install decent drainage so the water can run away effectively. My house is located in Kingsland, Auckland.