No problem, we've got the information now.
From what you say there would appear to be a problem with the heater.
It locks the door, takes in water and detergent which is correct and it tumbles the clothes.
If it doesn't heat it can stick on the programme, normally if it's an open circuit heater.
You'll need access to and be able to use a multimeter to test the heater.
Unplug the appliance and take the rear cover off.
At the bottom rear of the tub is the heater and thermistor (temperature sensor).
First check the wiring to these, give the wires a good tug as they can break internally leaving the outer sheath whole.
Take the connections off the heater (note where they go, camera phone is good for this) and using the multimeter, see if it's around the 25 ohms mark.
If it's open circuit or the reading is a lot higher than 25 ohms (allow 10 ohms maximum for the multimeter leads and calibration) you'll need a new heater.
Check it out, see what you find.
Hope this helps
Let me know how it goes or if you need more help.