iTunes account

So I have a MacBook pro an got a iPad recently. When I got my iPad I created a iTunes account. Later on I couldn't figure out how to put in a gift card an that account was like the family account. So I created a new account and started buying apps. About a month later it wouldn't let me update some of my apps. I figured that they were already updated but just showing that they weren't. Then it would show that there was something wrong with my account. So all those apps were from that one account. Now it won't even let me sign into my old account or let me update those apps. So why did apple decide to deactivate my account. Is it because I have two accounts? I really need to update those apps!!!!!!!
I AM VERY FRUSTRATED WITH APPLE!!!!!!!!!!!!!!!!!!!!!!!!