We have this issue with a neighbor. She uses our address for everything, even tho she has her own apartment, she's given out our address to all and sundry. We have been getting her mail for 4 years and have returned her mail to the senders, we have gone to the PO and complained, and we have complained to her. She admits doing it deliberately because she does not want to have to shovel out her sidewalk where the post boxes are, and "this is easier" for her.
my point is this could be a deliberate act on the addressee's part because he does not want to come down to the PO to get his mail...it's easier to have you send it either to him or return it to sender. All the benefits, none of the cost or hassle.
Honestly, this is not at all the same. The OP's guy isn't deliberately giving out an address that he had no right to--it used to BE his address. There isn't ANY indication that he is continuing to use that address at all--these are all residual things. He folded his business--he has no control anymore over what other people do with stuff they want to send him.
And he isn't GETTING his mail--it just gets returned to the sender. The OP had to go to some lengths to track down ANY address for the business. There is zero benefit to him.
The only part that is the same is that the post office isn't particularly helpful.