Can teens use cellphones? If they can't, where can I get a objects that can make my teen sims get cellphones?

Yes they can, but they need to buy one first. Send them to a community lot that has a phone vending machine. Once they've bought it, all you have to do for them to use it, is click on the active Sim, and an option will pop up for "call"......they'll pull out their new cell, and use it.