That sounds really bad. I had the (real) pleasure renting with JAP several times and noticed that they are slow, but cheerful. JAP has nice BMW's and I just canceled my JAP reservation making them SIXT which comes cheaper for the same car with Sixt Platinum status.

I also find it strange tat JAP is sold as SIXT, as I perceived JAP always as a low cost renter (with nice cars). And yes, the location is somewhat weird somewhere north-east from the airport and you get lost when driving out.