Who is at fault when a scheduler adds an unrequested Monday shift?

I work for a home health company where workers can pick up temporary shifts. The scheduler texted me that she had Friday, Saturday, Sunday, Monday day shift open. I texted back requesting to Saturday and Sunday. She texted me the patient details then when I agreed to work with the case. Scheduler texted me back a "confirmation" that I was scheduled to work. Apparently, this lady was stupid enough to text back saying I was confirmed to work Sat, sun, and Monday. Remember, I never asked for Monday. Unfortunately, I was stressed waiting to take a huge exam so I didn't read her confirmation text so I never knew she included Monday

Then after i finished Sunday's work, the patient asked if i was gonna come back to work for Monday. i told him no. there is someone else coming. Then as I went home, the scheduler called me angrily asking why i wasn't going to work on Monday. I told them I never asked for Monday. I have school on Monday. Then when I re checked the messages, I found out this dumb lady included Monday.

Now this lady refused to give me any more future shifts.

I don't think I did anything wrong. She made a dumb mistake and fucked up then tried to blame it on me.

Who is at fault when a scheduler adds an unrequested Monday shift?
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