Tvheadend

Hi together,

i have done a big mistake.
I tried to update to the 4.3 unstable from my 4.2.8 version.
But there error I why I was trying the 4.3 was still there.
So it tried to remove the 4.3 and install the 4.2.8 version again.

But all trying was not working.
So I'm not able to login in the system. Also the try to changing admin user name and password was not working.

Can somebody please explain me how I can fix this?

edit:
Here some more background informations.
I'm using tvheadend on Debian stretch.

Thanks a lot.

Cheers Robert