Changed heater control valve AND panel and still only hot air?

It's a ford ka…
Was blowing hot air out air con when switched off. So changed the valve and worked for a day then back to normal… Changed the panel (2nd known problem) and that hasn't worked?
When my engine is off… I can get cold air?

Change the setting from fresh air to recirculation then no air should come out of the event

Valve?
worked for a day then back to normal?
the panel?
"When my engine is off… I can get cold air?"?
Can't make sense of this just yet.