Essentially, some Turkish speaking Bulgarians(mostly roma, Bulgarians don't normally speak Turkish) would call random Turkish numbers, hoping for a middle aged or older Turkish man call them back. The scam goes like "I live in a poor Bulgarian village and my father/brother/husband treats me badly, how lucky I misdialled the phone to such a gentleman like you" and then they proceed to earn the mans trust and ask for money(first they ask for a bus ticket, then they will call back "on the way for Turkey" about something unexpected happening and ask for a large sum to be wired through Western Union).
I'm Bulgaria born and I happen to have relatives where some of the scams are run at. I've seen with my own eyes people camping in front of a Western Union branch theatrically pretending that they are at the Turkish/Bulgarian border and the woman needs to pay some large fine otherwise they wouldn't let her go to Turkey. She will hand the phone to her husband who will pretend that he is a racist/fascist/gestapo Bulgarian officer asking for money or else she ain't coming to you.
My relatives there told me that they even started scam courses with a week full curriculum where you pay the experienced scammers to teach you how to run the scams. They built some very nice houses in the region.
Anyway, it all faded away when Bulgaria made it compulsory providing ID when you buy a new SIM(10 SIM registrations per person per year limit is introduced). Probably as a result of Turkey asking Bulgaria to locate the scammers. I heard about some still doing it by using SIMs from other countries however the heydays are gone.