Politicians listen to lobbyists, but only to the point where their constituents remain silent. If it appears the majority of their constituents are opposed to something they will back off regardless of the amount of money they are offered. It all comes down to reelections (survival). They are acutely aware of how fast and unceremoniously they can be shown the door. Make sure your representatives know you will not vote for anyone that stands on the wrong side of any issue that is important to you. They do pay attention.