Don't just contact them once. Every time there's any news of consequence on the bills moving ahead let them know your desire to have them oppose them.
Thus far I've had responses from both US Senators, my US Representative, and the Governor. No response from the President yet.
The responses are obviously 'canned' letters. The important thing is that their staffs do keep a record of the number of contacts for each 'side' of an issue. Numbers count.