What are you gonna roast at 550? Have you tried 350? didn't the installer do a function test? Have you cut power to it and tried to reset it? If you followed all advice out there you couldn't buy anything. If defective it happens wolf has a fast turn around time and excellent customer service in most situations.

Are you sure the temp is rising from 100 to 550? On my Wolf L-Series wall oven it will toggle between the current temperature of the inside of the unit (100 in your case) and then the selected set temperature (550 in your case) as it pre-heats the unit. The 100 should increase over time until it reaches the 550, then our L-series makes a beep to indicate is has reached the set point.

Phil