Was sold a lemon. Options?

I will try to keep this brief.

I’ve bought several used cars in Japan (currently residing in Okinawa), and have never had any complaints or problems.

Last July, I dropped ¥920k on a 2015 Mazda CX5 diesel. I bought it from a small used car place in southern Okinawa, and the guy seemed very honest and passionate about cars. Told me I would love it so much, that my next car would be a diesel, too. Even let me test drive, which is rare here. It drove great, and when I asked about the price (most CX5’s that are a couple years younger are usually much more expensive) and if something was wrong with it, he said it had just been on the lot for a while and was great.

Obviously, I lacked some of the research skills on this particular model, which is on me, but this guy said his last car was a CX5, and the current manager’s car is also a CX5. Got the standard cautions that go with a diesel car and followed them to the T. Car comes with a 1-year warranty where parts are free, just paying for labor.

The day after I brought it home, the starter died. Apparently, it was the “only thing they didn’t check.” Replaced it for free, but when I called, they told me it was my fault “for buying a used car.” Instant WTF.

One month later, oil problems start. I am gaslit by this guy every time I call, telling me 「中古車なんで壊れてもしょうがない」and changing the oil.

Every month, sometimes two months, there’s another catastrophic oil problem. Oil pump got replaced for ¥42,000 two months ago, finally everything seemed great.

Yesterday, the oil lamp is back on. I’m honestly done. This guy never has a 代車 available, never apologizes, and somehow the fault is always with me for being stupid enough to purchase a used car, apparently.

I just finished shaken and contacted my friend who handled the car first, and he said there’s an issue with CX5’s in general, including some recalls, but there’s nothing I could do about that anyway, because it’s already had someone besides the dealership tinker with it. Reviews on this particular car are very split down the middle.

I know Japan doesn’t have lemon laws, but I’m going to call #188 and see what I can do.

Ideally, since I’m still within the warranty period, I’d like them to buy the car back, and I don’t even know what to expect back if they do. Hoping for ¥350-400k of the original ¥920k, but is that a total pipe dream?

I don’t want to take them to court, because the legal fees will probably exceed anything I could get back, even if I can get anything out of it.

I just want a flipping car that drives for more than a month without having problems.

Has anyone else had a similar experience, and if so, how did you handle it? Am I cooked? Is there hope?

If there are any other numbers or organizations I can call, that would also be great.

Thank you in advance.