That's what I did to get into this mess - VPN was not working. Recent need to uninstall/reinstall ASB to try to get the GD adblock working on my PC made me think I would do the same with the VPN on the device. After I uninstalled VPN, I could not reinstall as PlayStore keeps telling me it's already installed. I cleared data & cache on device, did a restart, no change. I am trying to get a new version of PlayStore to download atm. Would be much easier if I could get VPN (that I'm $ubscribed to) in a more direct manner.
Edit: Yeah, I can't seem to rectify the "DF-DFERH-01: Error retrieving information from server" problem on the PlayStore app.
I'm stuck.