Bryant 80% and a plus 90% furnace no heat but ac unit runs while on heat. What can I do?

Are you sure that you do not have a heat pump system. Do you have a switch on your thermostat that says "emergency or alternate heat".

A heat pump will run when the thermostat will run when set on heat.

I am not telling you this because I think you are dumb, it is possible that you may have just moved in or something.