A renewal charge usually looks unexpected for one of these reasons.
It arrived before the due date. Invoices are issued about 7 days ahead of the date the service renews, so the payment is taken before the new period starts. This is deliberate: it keeps a server from being suspended over an invoice that had no time to clear.
The amount does not match the plan price. Upgrades and downgrades are prorated, so the first invoice after a change covers only the remaining part of the period and looks like an odd number. Tax and currency conversion are applied on top of the listed price.
There appear to be two charges. Ordering a second service, or an order placed twice, creates a second invoice with its own renewal. Check your services list — if there is a service you did not mean to buy, tell us and we will sort it out.
If none of these explain it, open a ticket with the invoice number or the amount and date from your statement, and we will trace the charge.
If you need help with this, please submit a ticket.