There could be a number of reasons I won’t reply. The most likely reason is I simply didn’t get your message or letter. No system is perfect, and any computer can have a hiccup. Another option is I severed ties with you. This could be because you choose to not respect my requests, or wishes. I could also not reply because you were vulgar. Another reason I may not reply is if you wrote a letter or email and at best – you wrote a sentence or two. If you aren’t going to take the time to write me, I am not going to waste my time writing back.