After my car check on which I warned them of an issue, I received the bill (~1500 EUR) and assurance that there is no issue with the car.
2 weeks later I left on a road trip and the car failed on the issue I mentioned.
The high incompetence of this company cost me over 6000 EUR (aside the payed service) 1 week on the road and high security risk driving a faulty vehicle.
Unfortunately I couldn't do much because I'm a small company therefore I wasn't covered by consumer protection and I do not have the means to fight in court this company. I am happy I can give them 1 star, but in truth they are not worth even that one!