They came round to do my neighbours roof, ended up trespassing on my roof without permission and smashed a window. They then said they'd fix it on the day but left without resolving it.
The window they smashed was to my 2 year old daughters bedroom leaving shards of glass on the floor and loose shards still in the window.
I was offered vague apologies and asked if I had tools and materials to fix it, then when I didn't have the tools to fix their error, they seemed at a loss at to what to do.
If that's how they deal with mistakes, you have to question the rest of their build quality.