Well I'm also a victim of windows phone lumia 1072-RM.
I reset the phone factory yesterday that's 06/Jan/2020.
I have sign in one account using the Google account but when I try to sign in the Microsoft account, it appears "can't connect". "We are having trouble connecting to the store right now. Try again in a little while".
If the MS account cannot open then there is no way one can be able to use the store to install Whatsapp
Messenger on to the phone. Please I bought mine and it worth a cost, so I can't spend another money on phone again. It hurts to buy phone while my current phone is still working. I beg MS to work towards the situation.