Lost Access to Network admin and the WordPress username changed automatically

Hello, I ran into some problems Today when I tried to log in to the admin panel in WordPress using it shows that my username is wrong then when I tried with my email it shows that my password is wrong and now when I tried to log in after forgot password and reset password. And hopefully, I can log in with my email as I can see that my default username which was previously Reetanka was changed to kontol. But how’s this possible and now the main problem is I can’t access my network admin area so I can’t install plugin or something at all. I need urgent help regarding the issue!!!!