Opel Grandland Chronic Timing Belt Problem

When I left my 2020 model Opel Grandland with 57,000 km for its 60,000 km maintenance service, I wanted them to check if my vehicle had the timing belt issues that I had read about on domestic and international forum sites. During the service inspection, they informed me that the timing belt was worn and needed replacement. I mentioned that this problem seemed chronic in these vehicles. They assured me they would contact the Opel center and provide a response. Later, they got back to me, stating that the Opel Center had agreed to cover a portion of the cost, but the total would be 9,000 Turkish liras. I agreed as it was our only vehicle, and I wanted the issue resolved promptly. Two days later, the service contacted me again, saying that in addition to the timing belt, they also needed to replace the oil pump and electro valve, which would cost around 40,000 liras. I couldn't afford this additional expense, so they advised me to contact Opel headquarters. I reached out to Opel headquarters, explained the situation and a case was opened. They assured me they would respond. It's been a month since I left my vehicle for service, and today, the service informed me that my request was rejected because I had previously had maintenance done elsewhere. I find it inappropriate for a brand like Opel to attempt to downplay this recurring issue in many Opel vehicles, both domestically and internationally, by using such excuses. They offered a 30 percent discount plus an additional 3,000 lira reduction in the cost. I insist that this issue be resolved in a manner befitting a global brand like Opel.