The People's Operator has a US based customer service team. They are positioned as a carrier who is socially conscious and they will donate 10% of your monthly bill to a charity of your choice. You don't need to do anything, TPO will take care of it all for you.
Seashells contain calcium carbonate. The calcium carbonate reacts with the acid in the vinegar and causes carbon dioxide bubbles to form. Even though the acid in vinegar is weak it can, over a period of time, dissolve shells.
Part 1: Calcium carbonate does come from the shell, exoskeletons, and skeletons of dead animals, usually those that died, deposited in water, and settled at the bottom of an ocean or a basin. Water does amazing things with ionically bonded compounds, and over millions of years dissolves much of this calcium carbonate.