Job Offer and Employment Contract
 

I applied for IT position in the company. Two weeks later, the HR of the company called and spoke to me on the phone. The next day I received an email asking me to come down for an interview, I acknowledged the email and confirm my attendance for the job interview.

Two weeks after the interview, the HR called me again and told me that I am offered a position and I shall wait for the employment contract through email.

I waited and waited for the email to come, but they never come. Then last Friday I called the company and asked but only managed to speak to different HR personnel. She told me she will inform the other HR about the me and the employment contract.

Now, already one week I have not heard or received any news from them.
I am desperate for this job, what should I do?
Should I call them again and ask about the employment contract?

Thanks and I appreciate your advice.