GROUNDHOG DAY!!!! SANNCE DVR KEEPS REVERTING TO OLD SETTINGS AFTER REBOOT

[chantelle 0]

i swapped with someone i care about with the same model but unfortunately i am now left with a problem i cannot fix!!!! it says changes were succesfull just need to reboot, then lo and behold the old settings are back, i have changed the cr2032 battery, formatted hard drive, un plugged and replugged hard drive, restored to defaults, even tried doing it via ethernet and ip adress online the only thing i not tried yet is firmware update as i cant find one, the dvr is sannce ( probably some shady chinese company), is it possible i can just update it from a trusted better known brands firmware??? , i have wasted hrs and hrs getting on to days, weeks even and it completley baffling me, also this dvr wont connect to internet saying change  dns which dont need changing but does connect to cloud via xmeye app also i am sure as i checked b4 swap my dvr only had 1 default user b4 and theirs had 2 a admin account and default user account neither of which can be deleted as both say reserved user BUT now they both have these 2 user accounts, does this mean someone is hacking in somehow and created this extra account........its weird as i remeber the one that only had 1 account im pretty sure was the default user account even though id have thought it should have been the admin one,............on th positive side the good news is i know a hell of alot more more about cctv than i did last week!!! not sure if worth adding that the only way to stop it rebooting and never change my settings is to keep ethernet in and i dont want to do that as dont want it to be online/hackable