Hi from Aussie

I have the following formula however only the first two requirements show up
- anything under 12 continues to show the "Warning" sentence - What am I
doing wrong please?

=IF(M2=0,0,IF(M2=16,"STOP You have reached EXTREME",IF(M2<1612,"WARNING
High Rating",IF(M2<1210,"MEDIUM Rating",IF(M2<810,"LOW Rating",SUM(M2))))))