To be clear I have paid the builder against our contract even though he has not delivered the job on time (so far 3 months over a contracted 3 months job).
I managed him more closely to get the job finished and today he just walked off the job and said unless I pay him now for the rest of the job he will not return the keys and he will render the electrics defunct with a remote device he has hidden in the building.
I think this is a civil matter (breach of contract) and a criminal matter (electrical device and property theft of keys).
How would you manage this? I feel threatened and vulnerable.