My PvZ 2 progress disappeared.

Have you registered your email with PVZ2 to earn gem reward before?  If you have, then you can try either install the game on a different device or perform a re-installation your current device, and then do the same email registeration to recover your old game progress.    

I have registered the email before and have already tried to reinstall the game.  This did not work.  I believe that EA will actually have to do something and restore the progress hopefully from a backup created before March 1st.

I see, when you re-install the game, normally, there should be an option to reload your old progres, were you not given a choice to select your previous saved progress after the ID conflict screen?  If this did not happen, your only option now is to contact EA Help Center by clicking the link at the bottom of this page and seek further assistance. 

I have already contacted EA Help Center, and they are pretty much useless.  No resolution.  I think I'm pretty much SOL.

There is one last thing I think you could try in this situation but this method requires access to another device.  

This is to do a fresh intsallation on a new device and try the email register again to see if your old progress is showing up as a selectable option.  

If your email linked account on the server has been overwritten or corrupted, then the only chance to have it recovered is with the helps from the help center's advisor.

the same thing happened to me just now and i did spend a fair share of my gems but i had almost 200 remaining yk thats still alot but i contacted the ea support and they are no help did you ever find the solution?