Yeah that’s a NCNS, regardless of the reason or if they found coverage for you.

if you don’t show up for your scheduled shift - it’s a no call , no show .
regardless if they found coverage
if you call out within the last hour of the start of your shift , there’s no reason for it to be a ncns , i mean it’s kinda messed up you didn’t give shifts advance of head of time , but you shouldn’t get in trouble for it (this is regarding the last part of your post)

it’s up to the manager’s decision whether it’s a final write up or termination .

it’s your responsibility to check your scheduled shifts daily and to show up on time . i would understand if you were scheduled without your manager checking up with you first but it looks like that didn’t happen .

Have you ever been written up before ?