I love how people say this and then don't help bot lane. If losing bot lanes makes you feel like you instantly lose the game, then help bot lane get ahead. That seems like a simple solution to me.
Alternatively, look at your team and see who can deal with the fed enemy bot laner. For instance, I had a game where the enemy mid and jungle came bot 6 different times during lane phase, twice the jungler came solo, and the other 4 times the mid was with him. They spent so much time bot that our mid lane Katarina who was 4/0 before mid started roaming bot and ended the game 15/4. Getting that Kat fed worked out because she blew up the 5/0 Vayne before a team fight even happened, didn't matter how ahead Vayne was.
Those are literally your two options, either help that lane so they aren't losing, or help the person who can shut down the enemy ADC.