Mercedes A 180d Check Engine Light On Again

The check engine light on my 2020 Mercedes A 180d turned on. Turns out, the problem was a busted cable for the heating spark plug. Just 11 months ago, the identical part was replaced under warranty at Kurtköy G***** Mercedes. Now, in under a year, the same problem has come up again. Even though I asked for a warranty replacement, they're saying my vehicle isn't covered anymore because I didn't change the transmission oil during the third maintenance. But during the third maintenance, I took my car to the Bati Oto authorized service center. They told me that I should change the transmission oil every 5 years or 120,000 km. Since my car has only been driven 55,000 km and is 3 years old, they said it wasn't time for a change. On April 2nd, I filed a complaint, but every time I check on its status by calling customer service at 4446244, they always say they'll get back to me soon, which makes me feel like I'm being lied to. Watch out, anyone who messes with consumer rights, because I'm taking this matter to the Consumer Arbitration Committee.