Jail Letters

I had been sending all these letters to death row inmates across the country, but now I've begun getting them back, unopened, return to sender. I wonder how that works? There's tons of sites online that offer prison penpals, and some of them aren't bizarre sex-ish sites. I realllllly need a prison pen pal because they are the only ones who can answer certain questions I have which need asking and which need answering.

Oh also this is my first post in over a year.