Question about the mp game modes

[stukabomber44]

Hey I just started play online I have a couple questions,

The following reinforcements are : No refund, With payback, and None.
Can anyone please explain clearly what these mean or what the differences are??

My other question is about the resource income (per minute) when I was playing with 4 people I noticed that I wasn't getting 400 resources per min, I was hoping for a massive battle, can anyone explain that to me as well??

I know I sound dumb but it doesn't explain in the manual or in the game.

Thank you.

SB44