I bought an AC750 dual band V5 RE190 wifi extender, after the initial setup  it ask me via app to update the firmware to the newest version, the problem after that is that I can't change the network name.

Every time I reopen the app the onemash feature is again enable...and if I try to disable it and change the name of the net for only one minutes the name is visible, but I it fail to connect to it and after a bit it disappeared and come back again with the name of my router wifi name. I try all your suggestion on the website, I try to downgrade the firmware but it fails everytime, I try to call from my nation help in line but the number isn't active anymore ( support.it@tp-link.com).

Also I try to reset the device via app and with the lil button, and I try from the start the connection to the router with all different device possible (the app form IOS and Android and the web page). But there is not use, after the pair is done I can't change the name of the extender wifi.