I’d get some guidance on this one over at CasinoMeister, @Jazzee.
Basically, on these games, a portion of the RTP is dedicated to this feature build. By removing the slots from play whilst you have progress there, they essentially owe you money. It won’t be a lot, as they could only refund you for the % which contributed towards the end feature, but they certainly can’t remove it and pay you nothing.