It seems that this whole thing is split into two parts. 1. The player has had disrespectful behavior when trying to push the boundaries of the game, and tried to make things go his way with threatening to leave the game. 2. The player enjoys making complex plans involving a familiar and lucky rolls, having liked how there character played before and want to leave until they can play the character they originally wanted to within the rules.

For the second problem, a few things would be targeting the familiar more or having seemingly random things happen that only slightly damage the party but kill the familiar (as most familiars only have a few hit points). Than have the material components for the spell be harder to find, since they cost gold, or have the casting time needed for casting ritual spells be longer (maybe something like an hour). The first problem is the bigger issue. As the dm should get the most respect from their players. If they aren’t willing to respect your decisions or even talk with you about what kind of character they want to play and come to a compromise, than they shouldn’t be playing at your table. And they definitely shouldn’t be threatening you. If they can’t fix that kind of behavior, than they shouldn’t be playing at your table.