I had that same bottle (until two weeks ago)! I think what works is to press the notches in (if you can manuver your fingers or nails to poke them in slightly) and then rock the top piece back and forth until you have eased it past the holes that the tabs slot into.
The problem I had with mine is that the "refill" bottle had stopped spraying even though there was a good half-ounce of Coco remaining. I ended up cutting the top off the bottle and pouring it into another bottle. I bought a new bottle in the non-refillable packaging and disposed of the old case.
Good luck with yours!