Latest questions about "message delivery"

I am puzzled by the following on Viber and would be grateful if anyone could answer: I believe I am blocked by a contact because every time I call person on Viber it shows up "calling" not "ringing"...

Will messages sent to me while I am out of range, be waiting and delivered to my phone when I return to being in range?

I sent a message to a friend on Viber. My friend was offline when I sent it. After 3 days, he got online and when I checked my message, it wasn't delivered to him.

I sent a reply to a friends message early this morning and it went through instantly and has 'delivered' status.

I sent a message to an iPhone. It took a little bit of time to get the delivery confirmation, probably because the person works in the remote area.