I need help with my website , having problems and cannot see dashboard for editing

I need someone who can sort out problems on my website .. I had a 502 error message and it wiped out my dashboard , cannot see it .so I cant edit anything . If I try logging out I get a 500 error message , technical difficulties. Ive been told it could be my plugins on WordPress and to rename in control panel but I am new to all this and wouldn't know where to start .So if anyone thinks they can sort out my problems then please send your proposals.
Kind regards
Rob