Keep the message simple. Here is an example.
Please support Representative Thandear Shri's Articles of Impeachment H. Res 353. President Trump has flouted the Constitution too much to let this go on.
Thank you.
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Let's get to writing. Tomorrow at noon (or as close to it as possible) flood your Congress Person's email with support for the Articles of Impeachment. You can find your Congress member's contact information here.
www.house.gov/representa.....
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Thank you

They will listen to it. And straight to voicemail means it is saved verbatim.