Accessing thermostat , Servis fridge freezer, M7666S?

I am trying to replace the thermostat of my SERVIS fridge freezer. (Double door).
The thermostat is located within the top (front part) cover. I unscrewed the three screws in front beneath the cover and unplugged the thermostat knob. But the cover catching on something. It is not coming off. I did not apply much force or tried to pry it off.
Can someone suggest an idea? Make : SERVIS, Model :M7666S
There are two serial numbers on the label in the fridge compartment:
200721120521-038077115-03 02