This is probably a bit far fetched but seeing as there is no paper work ring the cops and tell them that they offered to take the logs and pay cash off the books then came onto your yard got bogged returned the next day at a time not suitable (not supposed to start outside work until 7am I think) dug up the place trying to get their truck out and now wont claim responsibility.
Its your word against theirs if there is no paper work.
As I said its a bit far fetched
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