sentence correction Hello everyone, i think my sentence is okay but Microsoft word keep lining it in green. what do you think?? Studies shows that using mobiles for extended periods of time without headphones can diffidently have a negative effect on our hearing abilities.

IELTS first task, Please correct me Dear Mr. Ali, I am writing to you regarding the financial report that i was supposed to email you next Monday. As I will not be able to deliver it on time and I was hoping to get your permission for one week extinction. Due to the work force shortage we are experiencing at our office this period, it has been very difficult to devote myself to my routine job only. As you are aware last month we had to let go three of our employees to reduce budget. Moreover at this time of the year our sales in Alexandria are at its best that of course require more effort from everyone in our office. I realize that the financial report is crucial in the company next meeting on the 4th of March, so I sincerely hope you would accept my deep apologies about the delay. Starting from the upcoming week end I will be working on the report. I expect to finish it on Wednesday at most and will be sending it to you at the same day. Yours sincerely, Samah