If your Congressional representative does not support Medicare For All (single payer), run against them in the next election cycle or donate & volunteer for a competitor who does. That is all that is getting in the way of policy implementation, having enough votes to pass the bill in the House and the Senate. We'll get there!
I'm working on a site that will obtain attestation from Congressional reps as to their support for M4A, and for those who don't attest support, campaign funding will be funneled to competitors of said representatives who do.
https://www.congress.gov/bill/116th-congress/senate-bill/112... (S.1129 - Medicare for All Act of 2019)