This happened to us last year when we unexpectedly had to go out of town and didn't check our mail for 10 days... i hardly think that qualified us for the "this address is vacant" note. When I called the PO to complain and see if my mail was being held there, I was told they hadn't held it but that it would have been returned to sender.
It was a real pain to deal with all the companies (and a few friends) who had sent us mail/bills and let them know it had been a mistake. Ended up paying a few bills online that month and eventually things have been set right.
I recommend taking quick action and contacting the PO to let them know you are very much still living here. Also notify anyone you may have been expecting mail from to get things straightened out.
Sounds like one of the delivery folks is trigger happy about labeling addresses as "vacant." Good luck!
