I can only speak for my own experience, but quite a few tabs broke off on one of the sets I bought (a long time ago). I contacted them, provided all the information requested and have never heard another thing. No replacement lids either.
I simply tossed the containers with broken lids and haven't bought Lock'n'Lock since, other than a set of the Christmas bowls with gift bags that they did a couple of years ago.
Some people have had good luck getting replacement lids. I wasn't one of them and it was too much hassle to try to chase them up.
"" A little learning is a dangerous thing."-Alexander Pope