mixed voice broken

Hi everybody! For as long as I can remember I have had a broken mixed voice. The pitch and tone are very unstable, my mixed voice often cracks, and it sounds scratchy (not like Rod Stewart but in a bad way that grates on the ears). I have been to 2 doctors that specialize in voice and both have told me that there is nothing wrong with my vocal cords. I also have a problem with phlegm and with constantly clearing my throat in an attempt to get rid of it. But even when there is no phlegm and I'm not clearing my throat my mixed voice is still just as bad as ever, having all of the same problems that I have already explained above.

Is there anyone that can give me some advice about how I might fix my mixed voice?

Thank you for your time in reading this!

Thank you for sharing, Wally! Have you tried straw singing? Many singers have success "bridging the gap" between chest and head voice, and eventually finding their "mix" with straw phonation. 

This channel has lots of warmups - search for any that target mixed voice or male voices: https://www.youtube.com/c/SingingStraw.

If you've tried straw singing and it hasn't worked for you, let me know!

I recently filmed a 3-part lesson series called Mixed Voice 101 (for this website), and hopefully that'll be up soon to help, as well!

Thanks Camille! Can't wait to hear your mixed voice videos!

You're welcome, Wally!