Update: I don't have to pay anything! They had set the monthly limit to 6 GB, while in fact it's much more. They assured me I will not pay more for exceeded bandwidth either, they'll warn me first.
Dear Frank de Groot,
This letter informs you of how much was accrued/charged for the following operations:
Login: frank
Account ID: 2056
Plan: VIP
Order: #2046-2513-1
Monthly fee for VIP plan (1/11/06 - 2/11/06) $25.00
Monthly fee for extra 44,000 MB above free 6,000 MB of disk quota (1/11/06 - 2/11/06) $22,000.00
TOTAL: $22,025.00
YOUR CURRENT BALANCE: ($21,750.00)