Stick RPG (the original Flash game) does not have cellphones. It's a retro-styled, early-2000s life sim where technology tops out at:
If you're playing a modded version or a fan remake (e.g., on Newgrounds, itch.io, or mobile ports), check that specific version's wiki or Discord—someone may have added a phone item.
For a modern life sim with smartphones, try BitLife, The Sims Mobile, or AltLife.