Correction please

[LwyrFirat]

Dear X,

Hello Ms. X, my name is Y and I am an applicant to your xyz position. Yestarday when I was unavailable I received a call to my mobile phone, since I was unavailable my father answered the call. He said to me that "the call was from xy HR, and the lady on the phone told him that when I am available I can call them back from the same number". I tried to reach you by using the number that appeared on my phone, however I couldn't. Is it possible for you call me back?

Regards.

[2006]

Dear X,

Hello Ms. X:
My name is Y and I am an applicant for your xyz position. Yesterday while I was unavailable I received a call on my mobile phone, but since I was unavailable my father answered the call. He told me that the call was from xy HR and that the lady on the phone told him that when I am able I can call them back at the same number.
I tried to reach you at the number that appeared on my phone, but I couldn't. Is it possible for you to please call me back?

Regards,
your name here

If you really are applying for a job, it is best to use your own English, not that of another person. Your letter is very understandable.
If you want to know the reasons for the changes, ask about the ones you don't understand.

[LwyrFirat]

Thank you very much dear 2006, it was an urgent e-mail so I sent the one that I posted on the forum, so I used my own English as you advised. Thank you again for your help.