same here, mostly....
have a S20 with whatsapp, no problems at all.(until)
I then bought a JoyTAB 2, (tablet =0 phones here but DUO)
and made the blunder,, installed whatsapp on JOYTAB 2 (oops)
it works but now the S20 is dead for whatsapp. (not what I want)
it tells me, no contracts there on s20, now,
omg how to go backwards now?
how do I Regress my bad ACT..
please help. thanks to all.