Why AppSumo?

I live in Zambia, and one of the ways I have found of making an extra income is by selling my software as a service via appsumo.com.
This month, My dashboard indicated that am supposed to receive $750.89. Then someone from payments department of appsumo sent an invoice of $716 to Tipaltis ( The company that wires the money to my bank).

Here how this works, Tipaltis - deducts $10.00 as service fees, and my Bank deducts $7.00 as service fees for every transact that comes through from appsumo.com

There have been months when I had made one sell and after appsumo deductions, I remained with only $38.00 and by the time that money is hitting my account, its reduced to $24.00 (These times I felt like my work was so useless).
So after making a $750.00 sales, I felt awesome, knowing that when all deductions are made, I will have at least a $730.00 (Only to be wired a $716.00).

I immediately wrote to them, there response was that am not the only one facing the finances disparity (Money in the Dashboard and Money Sent Out) issues.

I feel like quitting appsumo for good and find other channels of selling my software.