First, there is no need to find an agent to apply for a Korean visa. You live in Guangzhou, so it is recommended to apply directly to the Consulate General in Guangzhou. The information is super simple and the cost is low, probably in 210 yuan.
Second, if it&;s too much trouble, it&;s recommended to find a Taobao agent. I went to Korea in April this year, because my home was not in the consular district before, and I found an agent online. The cost is slightly higher than that of the consulate, probably in 350 yuan, so you don&;t need a deposit, so you don&;t have to do it if you pay a deposit. Beware of being fooled.
Third, if Taobao is not considered, at present, many domestic travel websites have merchants who cooperate to apply for visas, but the fees are slightly higher than Taobao.
Fourth, finally, you can find your local travel agency, but th——100,000 yuan, which is more troublesome, but it is safe and reliable.