I feel like I'm getting abuse with outstanding bills

Hey, this is not the first time this has happened. I'm originally from Bulgaria, but moved to England and I often come to visit my family in here (Bulgaria). My Apple store is set in the UK with my UK card. Whenever I find an app I like, I buy it and the money is taken out of my bank account, ok fine, but now when I tried to update some apps it says I have "outstanding bills" and then I go check on the Statement that's on the Itunes for PC and it says I have not paid some apps??? On my bank statement I can see how much Itunes took out of my card and for what. This is really frustrating as it is not the first time it has happened and the first time I just let it go and paid again as I thought it might have been a mistake coming from me. On top of that, I have drawn out all my balance from my UK card to use it here and It doesn't let me change my region so I could put in my Bulgarian card to pay those "outstanding bills".....

Am I the only one having those problems? I'm usually a really patient and understandable person, but this is upsetting me a little.