I don't know much about this.

There are many instrumental music shops selling guitars and violins in Zhongshan. I wonder if they have any teacher resources. You can visit a few blocks (I know there are two shops near Daxin New City).

Or you can ask Boya Bookstore in Holiday Plaza. Boya Bookstore will have more teachers' resources. There is a vocal training department on the second floor of their bookstore, which should have piano, violin, guzheng and guitar. Ask the front desk staff to see if there is a suitable teacher for you.

Or you can find a college guitar lover. Many college students can play the guitar. It might be good to ask them to teach guitar. You can post in Zhongshan Campus of Guangdong Pharmaceutical University or Zhongshan College Forum to see if you can find the right one.

Good luck.