Opel Astra Excessive Repair Costs and Faulty Diagnostics

I recently faced a frustrating experience with my Opel Astra's servicing and excessive repair costs. Despite my car's high oil consumption, the Bursa Nilüfer service center charged me ₺2,000 for a checkup and claimed there were no issues. A few months later, when the yellow engine warning light illuminated, I rushed to the Osmangazi service center, where they performed a regeneration procedure and charged me another ₺2,000. However, the light reappeared after just three days.
When I contacted the service center again, they suggested replacing the catalytic converter at a staggering cost of ₺80,000. Fortunately, I sought a second opinion from a trusted mechanic, who identified the problem as a faulty LOG sensor, which would have cost only a fraction of the original estimate.
I am deeply disappointed with Opel's service quality and the lack of transparency in their repair process. Despite following the proper channels to file a complaint, the service centers seem unwilling to address the core issues or provide satisfactory solutions.
This experience has shaken my confidence in the Opel brand and has left me questioning the integrity of their service centers. I urge fellow Opel Astra owners to be vigilant and seek alternative opinions when faced with high repair costs or unresolved issues.