$15000 stolen from Plus500 account, page-18

Really simple fundamental question here...

Ofcourse CFD Companies charge for the transaction fee + they charge margin on losses overnight... But where does the profit come from, if my trade wins? Given trading is a zero sum game... With Securities. Other people loose when I win.

With CFD's. When I win... Is it the CFD Co that looses?

Let me provide an example:
Opening -transaction feesMargin fee's... (Lets say this totals $10)If I purchase a stock at $100.And it goes up by 100%.Now $200I decide to close the position...
Same figures againClosing -transaction fees,Margin fee's... (Lets say this now totals $20) Because the price doubledI am then due $170 (Minus $10 Opening + margin fee's -$20 Closing fee's)
The $70 difference Profit....

Does this come at a loss to the CFD Broker / CFD trading company?