Doesn't completely dry clothes

I have owned this dryer for about 3 months. Most of the time my clothes are still damp after a cycle. 99% of the time I have to put towels through another dry cycle. How can one save energy having to do that. Plus, if towels are left damp 24 hours sitting in a dryer you get mildew. I have contacted GE representative and checked off all their suggestions; also had the appliance store send out a repairman. The repairman said the sensor is working and nothing else is wrong. Something is wrong when clothes don't get dry. I had a Maytag dryer 20+ years and I never had that problem.