i am trying to call the embassy on the telephone number but unfortunately i couldn't reach anyone.

The hot line is busy in most cases, so it is not easy to get through.
If you want to apply for a 12-month multiple-entry tourist L type, you need to provide those documents including your passport and its copy, a completed application form affixed with a recently-taken bareheaded color photo, an invitation letter from a Chinese travel agency, round trip air tickets, hotel booking record, proof of your bank savings account, and maybe your employment certificate is also needed.
You can apply for it in person, or ask your friend to do it for you.