Mercedes benz leather seats

I bought a C200 in 2016 with AMG sport pack. It was fitted with "Artigo" leather seats. 3 years later my right hand seat started cracking and peeling off. Contacted dealership in secunda and was told warranty has expired. I was so disappointed with the quality of Mercedes benz. How can you have a seat cracking and peeling off in 3 years? My car is still covered by maintenance plan.