My job

last week l made a mistake with my job, I had a 4 days vacation. before I left the office, I transferred the job to my colleague to help me deal with it but my colleague forgot to follow. When I got back to the office, one of the emails I sent to my boss, she'd reply to me about the email. In it she scolded at me, that I couldn't reply it to my client on time. I admitted to the fault and learned from it. in fact, I think it is not very important for customers because my customer dosen't require me to reply it  immediately. but my boss is angry about this matter, and i feel  very bad in  my heart.

I understood everything :)  Capitalization and tense are most of the corrections. The story occurred in the past, so it should be in the past tense.

Blue: Grammar/Capitalization/Tense
Green: Replaced a word/Insert word/spelling
Pink: Suggested change/more natural sound

My job

Last week I made a mistake at my job.  I had a vacation for 4 days.  Before I left my office, I transfered my job to my colleague to help while I was gone.  But my colleague forget to follow.  After I returned to my office, one of my email I sent it to my highest leader[...?].  When she replied to me about the email, she scolded me for not replying to my client in time.  I admitted the mistake and learned from it.  In fact, I think it is not very important to the customer because my customer didn't require me to reply to it at once.  But my leader is angry about this matter, I feel it is very bad in my heart.