Ok let me try to help.
Question: How do I get the cell phone?
Answer: From entering all the V4 Shop codes, which you can find
>>Here<<. You can only use the cell phone when your tamagotchi is in the Adult stage, and Grandparent stage.
Question: How do you call your parents, and grandparents?
Answer: Go to the book icon (9th icon), go to "Family", you should see your previous tamagotchi's, you must be on a higher generation than
Gen1, press the B button several times or once, and they should give you some codes.
Right Arrow = C button
Left Arrow = A button
Circle = B button.
Also if you want to call additional friends like teachers, and etc look at this topic
>>Here<<
Wow, while doing all this topic I didn't notice their was a FAQ on it, on tama-zone
Click.
Hope I helped.