I noticed my heat was running even when it got to set temperature. Tried to turn off and turn on fan. Fan went off first time but tried again and fan stayed on. Turned down to 67 and unit cut off. What should I do net.

Your system will likely have On or Off delays so you can't short cycle the system and burn out the motors by doing what you are doing. Otherwise, your thermostat relays may be crapping out and you may need a new stat.