Issues with Voltcraft IR 900-30S pyrometer

[Magnifito]

Hello!
As you may see I'm new here, but I hope to find this forum a good ship for me as I embark on my journey in electronics world.

Let's get to the point. I bought in an auction a Voltcraft IR 900-30S pyrometer for less than a half price (~45$ instead ~106$). It was sold as "retourwaren" which as I presume is a german term for equipment returned to the seller. It should be in working order and if it isn't I have 10 days to send it back and get my money back. As it turns out it works really well showing my desk's temperature or my freezer's. I tried to measure my body's temperature and it shows 30 degrees Celsius. I thought "it isn't made for that purpose", but when I measured my oven which should be over 200°C it still showed 30°C, next was my heat gun and boiling kettle and they also were 30°C. The K type thermocouple works perfectly fine, it's the IR measurement that have issues.

Should I return it or I'm doing something wrong? I'm well aware of shiny metal objects, spot size vs distance and different emissivity of materials.

Here's some basic specification:
30:1 optics
Temperature range: -50 to +900°C
Adjustable degree of emission
Measuring range K-type: -50 to + 1370 °C

Thanks in advance!

Edit:
I'm not sure if this thread should be in "Test Equipment" or "Other Equipment & Products" so sorry if it's in wrong section!