how to ship cargo from korea to new jersey

so i am concluding my time in Korea. looking at the amount of stuff i have in my house. i figure best and cheapest way is to send it overseas by cargo ship. 

now the problem is i have no idea where and how to do that.

i know about the post office ones but the boxes there are too small and the weight limit is not so good. (box size 5 and weight is 20 kg = 48,000)

i would like to send all of my stuff in one big box so everything gets there at once. i live near gyeongido so i assume i will use the port at Incheon to ship my stuff out. 

if anyone has any advice please please let me know! i am desperate!!! thank you so much!

Re: how to ship cargo from korea to new jersey

Uhm... Do you mean all your stuff weigh 20kg?

And how big is 'box size 5'?

I know the box 5 selling in Korean post office is 48x38x34cm. Is the box you mean is this box?