Business visa M

Good evening,
I am Peruvian and hold a Chinese tourist L type at the moment. I am in PRC currently. A Chinese company, that has business relationship with my company, has invited me to stay for 3 months here. They have given me an invitation letter.
I am going to Seoul on Monday, and planning to apply on Tuesday. Since I will show all the requirements they ask for, to grant me the entry permit, is there a possibility to fail in this?
If I apply on Tuesday at 9am, asking for the urgent service, could I get it on the same Tuesday? Or will I have to pick it up next day at 9am?
Is the address: "50-7, No.2 Street, Namsan-dong, Chung-gu, Seoul", the correct one to go and apply there?
I will really appreciate a soonish answer. Thanks in advance!
Marco