The "we don't have that data any more" should only apply to "I closed my account" not to the "we unilaterally chose to close you're account and delete all your data just because we can". And if they jumped the gun and can't, they must pay for the prejudice. Period.

They bet on people not suing and they're right most of the time customer don't demand. It does not mean, just because they actually get away with it by play dumb, that there are not legal basis.

It would certainly be interesting to see the limits of that law tested. Does a fragment in a cache count as them still having the data? What about a copy in an unallocated block on some disk? What about traces left after the data was overwritten (no storage medium is just bits at the physical layer) - are they obliged to extract every last bit that is technically possible?