To beat the "Full of Premium Wool" quest, get the "Premium Button" upgrade and max out "PREMIUM" upgrade. Then, go to the premium content in the menu screen and press "GIVE IT!". AND THEN YOU WAIT. Do this before you complete the game.
Guys, the bug where clicking the buttons on the title screen no longer works is caused by the last "button style" upgrade. You can get every other upgrade in the game safely, including every button style upgrade except for the last. So do not buy the last one until you've gotten the premium content quest, or just never buy it at all unless you want all the metals! Also, for the "Full of Premium Wool" quest to trigger, you have to listen to it until the end.