Can you get lost with a GPS?

My sister and I went to Kansas City the other day and she has a brand new gps. Problem is I'm just not sure we knew how to operate it. We were in a new section of town and just couldn't get it to work right or we just weren't operating it right. I honestly think the last was the truth. We finally gave up and used the KC map. When we got back we were right there was a problem with the gps and she had to take it back and exchange it for a different one.