I had the same one, it came with a vanity w.c. The Bellows behind the button stopped working, so took them apart and greased them up and all was fine for about a week.
Then they stopped working again, the valve passed slightly too and it was only a few months old, so my advice would be to change it for another brand and don't try to replace like for like as in my case it was a terrible valve.
Link to my thread about this valve.