In around 2005, somehow, a company mistyped a fax number to my home number. At around 2-3AM, I would get a call from a fax machine. I did not have a fax machine and if I called back, the call was answered, obviously, by a fax machine.
At first, I ignored it, thinking that they would obviously figure out that they had a problem when the receiver notified them that they had not received the fax.
After a week of one call per night, I put an old modem/fax into my computer and set it to answer.
When the fax came in, I received it. It was definitely Asian characters (I did not know which language). I took the fax to work and showed some of my co-workers.
One of my co-workers was able to read it and identified it as an invoice. At least I knew that eventually, someone would realize that they weren't getting paid.
I asked the co-worker to use the same language and write that the company had the wrong number and to check what the correct number was. When I got home, I faxed that back to them.
I was sure that was going to be the end of it.
The next evening, at around 3AM, the phone rings again. The computer/fax answers it and receives a fax.
The fax simply stated "Sorry". And that was the end of the 3AM calls.
Wow! Good job solving that problem and resolving the issue!