Yamaha Motor India — engine gasket cover gets damage

Recently I bought a r15 v3 bike in mumbai. Few days ago the engine oil start leaking from the head of engine. Then i complaint it to clear the problem in showroom. They said me that your bike engine magnet gasket cover gets damaged due to some reasons & they also said me your bike engine casing also get a cracked thats why the oil was getting leaked. I have a questioned that within 2 months of new bike how the engine magnet gasket cover gets damage? & casing also gets a crack? How the new bike have an internal issue?