Will I be considered as a very rude person if I call my teacher to check an urgent email

I got three recommendation letters from three of my former school teachers (professors A, B, C).

On 20th Jan, I got an email from the graduate school that I had applied to. In the email, they told me that they had received the confirmations from professors A and B, but are still waiting for the confirmation from professor C.

My application will be considered as successful on condition that they have received the confrimation from professor C before 30th

I have sent at least ten emails to professor c for the past few days, but not seen any replies from him.

I have got the phone number, fax number, and address of his office in my former school.

Since my former school is a few hours by bus away from my house, and I can not reach him by emails, I am thinking to call him directly on his office phone number, but I am wondering if it will make him very angry or I may be getting scolded by him.

What shall I do?