Here are the possible solutions if they don't fix it, you will want to find the authorized repair company as it is a control board issue.
1. Remove all your wine and beer and place it in your regular refrigerator.
2. Unplug this refrigerator and leave it alone for 24 - 48 hours.
3. Go purchase a refrigerator thermometer and put in in the refrigerator.
3. Plug the refrigerator back in and set it to the temp you like to keep it at. Do not put anything back into the refrigerator yet.
4. Check the temp of the refrigerator against the refrigerator thermometer - it is not unusual for the thermometers to be a couple of degrees in difference. If everything is acceptable, only place the wine back on the racks, leave the beer in the other refrigerator. Let it run for a week and see if it stays balanced.
Or - if upon initial check you find the two thermometers not agreeing you can do one of two things.
A. Best option - contact authorized repair and have them come fix it.
B. Leave the refrigerator thermometer in the fridge and adjust the display panel until the temp in the refrigerator is where you want it on the refrigerator thermometer.
C. Dispose or replace the refrigerator.
Note: I don't suggest overloading your refrigerator.
The original owner's manual is available here (I believe the last two letters designate the finish for example SS = stainless steel).
DIHL WF 21BD Instruction Manual