Too true MS. I love my little Garmin handheld. Its been utterly reliable though admittedly I only use it for heading and lat/long. That said we still have a back up and like you I carry paper. Indeed , offshore I'll still plot to paper even though the positioning is done electronically. Quite frankly its part of the enjoyment.
I do wonder though how , in your case, Garmin could get it so wrong. It s nott as if they do their own mapping.
“Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.” Terry Pratchett