...sigh, this Apple repair center you're going to is doing a sloppy job!
Sounds like they didn't attach the MacBook display lid sleep sensor by not putting your MacBook back together correctly.
Just to be sure that it's not software related, does it sleep from a clean installation?
When working correctly, the MacBook will go into Sleep mode when the lid is less than a half inch from being fully closed.
If these are warranty repairs (from what I've gathered from your other posts) then I'd look into a different Apple Authorized Service Provider or calling AppleCare and asking if you can send it in.