Can't turn off the heat. Still blows through closed vents
 

I'm trying to figure this out and it keeps getting worse, day by day. I have my air turned off, my ac has a leak so I don't get any cold air. so it mainly blows hot air. Ive closed the vents and set it all the way toward to cold side on the temp control but somehow it's still blowing hot air through all the vents on the dash and next to the radio, and now it's not just in my face but also on my feet. Any help on this would be appreciated.