I sold two pokemon that both gave me $6bil each but for some reason i lost 4bill each time, so that amounts to 8bil, is this a glitch or is there a cap rule that i don't know about? If this is a glitch how/can i get my lost money back? Ps how do the bank safes work?

There's a cap. I forget the exact number, but it's 2bil, 147mil, and some odd number cash.

so how do i keep from losing money when i get over cap, i purchased the titanium safe i just don't know how to redeem it when needed, and thank you.

Don't sell pokemon that are worth over the money cap as for safes you can't open them after you have bought them