Ed, I assume you are a shop and in business. If so, my bet is a disgruntled employee or customer. It's easy to call in and complain, they have to act on it. Had it happen to me years ago in the school welding shop, lasted three years, when one kid graduated, I haven't seen them since (knock on wood). I always asked if it was "so and so" and the guy would not say a word. It is an easy and anonymous way to hassle a person or business.
God and family, the rest is icing on the cake.
I'm so far behind, I think I'm in first place.
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