Full Sim Capacity

I'm trying to get to level 10, I only have one more requirement. The requirement is to add one more sim, it says "Add Sim (8/9)"...when I try to add a sim it says that my sim capacity is full. I tried saving my data to uninstall and reinstall the game, this didn't work. I tried restarting my phone thinking my phone was the problem, nope. I tried removing a sim from my town to drop it to 7 and then adding another to bring it back up to 8 but it's still saying my sim capacity is full. The only way to up my capacity is to level up (which i cant do without adding a sim) or by buying vip, which im not doing. I'm just confused as to why it says my max capacity is 9 but me having 8 sims is somehow too much??? Please help.