Hi.
As @Pr2 writes, all Enigma2 changes you made last will be saved safely.
However, if you press the mains switch at the back to turn off the set top box from electricity, the settings do not have to be saved in Enigma2 (it depends on the plugin or Enigma2 whether it saves the setting as "force" with every change or whether it only happens during standby mode and when rebooting the set top box). Rebooting should also help, as well as standby - the settings will be saved from the RAM memory to the internal disk (files in the folder: /etc/enigma2).
If you want to verify that this is not the fault of some plugin that always returns everything to its original state after booting, delete or edit the list manually. So, as first, for sure, stop the Enigma2, using the terminal, with the command:
init 4
(this step is not necessary, but just to be sure, you can do it for testing)
Then edit the userbouquet files (channel lists) as you need. Use, for example, E-Channelizer or DreamboxEdit (the FTP connection will still work and you can do it with it).
Then just start Enigma2 again and check how the channel list looks like.
Finally, to be sure, also reboot the device (via MENU in OpenPLi !!! not by turning off the set-top box from the mains + turning it on). After rebooting, check the status of the channel list again.