Account Summary problem

Account Summary Amount due as of 6 May is AU$2.97(I make regular payments to keep it down). On my New activity not yet invoiced 7th May totals AU$116.40, I could not have possibly accummulated this amount of new activity in a matter of hours. During April I changed my Store back to Basic Store, this has not shown on my Subscription Account. My account is showing listing fees at $1.65 each listing with Nill credits, I am supposed to have 600 free listings a month with my subscription (Basic Store). Something has gone haywire with my Account.

Sam