Typically, the refrigerator control is the thermostat, the freezer control opens and closes an air duct from one side to the other.
Like the others say, set the controls in the middle. Change the controls one letter at a time, and wait 24 hours before deciding if you want to change it one more letter.
If you set either control to the max one way or the other, you usually create more trouble than it's worth.
I changed a compressor last week for a very intelligent lady. She called back the next day to tell me the temps were off (20F freezer, 50F refrig). We spent several minutes on the phone, and finally I figured out she turned the controls to max cold, to get the thing going. Wrong thing to do! I suggested she turn them back to where they oughta be, and quit trying to get the machine to do things it's not designed to do. I havn't heard back from her. In the service industry, if they don't call, it's working fine.
Makes me wonder if you've got the knobs reversed, or if you're turning them in the wrong directions? Or if there is some other problem like a bad evaporator fan. Hmm.....