Their press crushing buttons on my shirts all the time. And when they replace crushed button they may use white thread with black button (while black thread used everywhere else) or black button instead of blue. I used them 5 times and now I have 4 shirts with some buttons missing and no spares. I understand that sometimes its OK to happened, but at least try to match colors - your customers are not blind.
It never happened before and once I start going to a different place - no more crashed buttons. This place is cheap but doesn't worth it.