At least you are lucky they drop in a card to say they had been around. The last one we had gave my wife a mouthful of verbal, just because she asked who he was and what was he doing.
She had never been home when they have come around before and was wondering who the stranger was making his way around the side of our house. When she asked him he got abusive.
Reported it to AGL and have not heard what was the outcome
