Looking at the back of your phone should normally give you the manufacturer name or logo and sometimes it will also state the phone's model, but it usually won't have the full model number. There are ...
You can't know for sure if someone has blocked you on an Android without asking the person, but there is a method you can use ...
To call your voicemail on an Android phone, open your phone's dial pad and hold your finger down on the "1" key.