My complaints is that why same model, colour and brand, but 2 different leather quality.

I suspect they use cheaper bovine leather for the later batch.

The leather quality is very obvious.

If you use your finger nail and softly scratch it, the leather will peel. That's how poor quality it is.

And after using it for few month, the leather begin to feel sticky and shiny.

This does not happen for the earlier batch, which my parents bought it last year.

Another problem with Rozel customer service is, they are defensive and denial all the way without understanding customer complaints and do an investigation.

Rozel brand sofas are not cheap. And you get this quality and customer service.

I might as well get a cheap brand and live with it.