sorry to hear! if you aren't confident with the front because you've just picked it up in spaces like that, try reversing as the backs much higher
hmm have another go at clipping it in, I'd jack up the front and get underneath so you can see whats happening.
When I picked my car up, the same side was actually hanging out a tiny bit and I had to clip it back in, salesmen probably did the same thing you did or when it was coming off/on the delivery truck...
definitely jack it up though and get your head under there, make sure nothing behind it is broken where the clips are meant to sit in. Worst case scenario you might be able to get some 3M tape and maybe put it back on if the clips are broken on the bar? let us know how you go