avoid at all cost
Called the service for a blocked toilet on a public holiday. After some time, a gentleman showed up, in a very small car (Nissan Micra or something of similar size), with no tools whatsoever. He claimed he's a plumber from Sanitärhilfe Vorort. He had a look at the toilet, and then told me that the minimum amount it will cost to unblock the toilet - just for the first hour - will be around €700. With an additional €700 for every additional hour. As I'm not the owner of the house, I declined. He then charged me €100, just for showing up completely unprepared, and telling me about the cost. He claimed I had to pay in cash, as there was a 'software update' for their card service scheduled for that day. After I paid, I called the company again, they confirmed that this was indeed their employee.
My impression was that he's just driving around from customer to customer, advising them about the insane cost, and collecting money for nothing. Without being in a position where he could do any actual work, because he had no tools.
I had the toilet blockage repaired by a real plumber later that day, he charged €90, including VAT. He showed up in a van full of tools, the first two devices he used alone were too large to fit into the car from Sanitärhilfe.