Edgars statement not received and amount payable all of a sudden changed even though I have not used the account.

Hi. I have not been using my account just paying it off but my monthly amount payable has all of a sudden doubled...how can that even be if I am not purchasing anything. I have also not been receiving statements anymore and when I phone an request they say they say they sent it but I don't receive it. This has all happened in the last two months with RCS.