Thank you for reaching out to the Community about your account! I can understand how important it is to fully understand the charges on your account. Have you recently updated your account to our Email Plus Plan? Or uploaded a large amount of contacts that have pushed you over your contact limit?
We have seen these reasons (along with sales tax) to be reasons for a price increase on an account. With that said, for your account security we are unable to go into your billing details here in the Community. Instead we ask that you please call into our Billing Support for any further assistance.