Furnace question.

Ok so this is my first time living in a house. We’re renting and it’s a townhome. Well ever since it’s been hot outside we’ve turned on our AC and set the knob to 60degrees but my house is still always 75 degrees. No matter where I set my temp the house is always hot and saying it’s 75 degrees in here. Is the furnace broken??

Sorry if it’s a dumb question