Short telephone interview - I need help

1. TELL ME ABOUT YOURSELF: I'm 31 years old and I have a degree in anthropology but for six years, I have been working in an Autodesk Training Center in Palermo, my Hometown.
In my company my main responsbilities are the management managing of training activities, the preparation preparing of estimates of cost, and creating invoices the invoice creation. I also provide information to customers and I create calendars for the course lessons. I request payments and I deal with collecting debt by sending a notice by mail to customers or with a telephone call.

2. WHY DO YOU APPLY FOR THIS JOB AND WHY DO YOU WANT TO LEAVE YOUR CURRENT JOB?
I am applying apply for this job because I would like to work in a big company, in a dynamic, innovative and multicultural working environment. I want to leave my current job because my company is a little reality with no possibilities to grow professionally.

(Note: I put this sentence in yellow because it may be a bit too harsh to say at a job interview. You may just want to say: I want to leave my current job because I would like more advancement opportunities and my current company is too small to provide such opportunities. )

Side Note: Some of my corrections I made were just to make your English sound more natural. The think over using the word 'the' can be bad. But if you don't like the changes. You can use your original phrases, they weren't bad. Good luck on your job change!

Can you correct my mistakes please? Thank's so much!