How to Contact the Family
The only way to contact Goku's family is to master the move Instant Transmission and learn telekinesis. Instant Transmission is a move that lets you transport anywhere you want to go in a matter of seconds. To preform this move, you put your index and middle finger against your head and think of anywhere you want to go and you will be transported there. Since Goku's family doesn't use phones or any type of device that helps you communicate, this is the only way to reach them.
Goku using Instant Transmission