it should still be in the wild, i didnt no you could get it in pvp, then again i havent played pvp in absolutely ages. before we could get cash in the game.
moga cash drops in wild fights is rare. remember to fight levels that are within two levels of your moga.
This happens most of the time due to leveling the wild ones to yours, but if you start out fresh with a group of say, 3/3/6 you'll get lvl 1 or 2 moga (near the start) which means only your lvl 3 moga will actually be able to net you a card or cash.