Did the person leave their name? If so, call through the company switchboard, employees tend to take calls that are transferred internally
Things to remember:
There may be a company operator. If that person asks the nature of your call, say you are returning an urgent call from X regarding your employment status.
Once you get the person on the phone and have said Hello X add: Sorry I missed your call yesterday, I am very interested in the job so I am very pleased I am able to reach you.
On your next call please say (slowly) your email address if you have one, thus giving them another option to reach you.
Lastly go to the company's Contact Us page on their web site, sent the person an email, state in the email, that the email is for X manager. Tech support will forward it and they will read an email tech support.
A good rule of thumb is call around 4:20 - 5:00PM many managers are likely at their desk tiding up for end of day
Continued success in you job search...