Robbed of intimacy (again)

My mother is now a widow.  In the past five weeks, I have written her four or five, maybe six, times.
She has, thus far, not received a single of those letters.
This is very upsetting.
I take for granted that governments are able to read mail, but to confiscate letters?
Do they do that, too?

I wonder how many people understand the intimacy of a genuine letter.  Not something with the speed of an email.  Something which is a private conversation, performed at a slower pace.

Every day, I ask my mother:  have you gotten one of my letters?  And every day, she answers that there was no letter from me.

Is someone stealing my letters?  For what purpose?

Has someone destroyed them?  Why?

I've also sent my mother pictures and poems.  Perhaps someone is laughing at them.

Is this merely an accidental tyranny?  
I don't know if that would be better or worse than if someone had specifically targeted me.

I sit down, and in my imagination, I am having a private conversation with my elderly mother.
I hope thereby to bring her some comfort, to make her feel less alone, to feel that life has possibilities, that things can be funny, interesting, whatever.

And that has been taken from me.  Why?