Only able to refer players level 10+ To stop alt cheaters

Currently you can refer players of any level and the referee player can earn prestige from it. This results in some players creating a chain or accounts which refer each other allowing each alt to level up a few times. Then these alts are high enough level to donate coins/cash to their alliance and haypi loses coin revenue as the alliance does not need to donate as much of their own.
By increasing the level which can be referred, this issue is solved because it would be a lot more difficult to get several alternate accounts to earn prestige and level up off each other.

Another solution is to simply remove refer prestige.