You could write to them (make sure that it is signed for at their end)
1&1 Internet Ltd
The Nova Building
Slough SL1 1XS
Phone 0870 24 11 247 (option 4) Mon-Fri 9am to 5pm Fax 08450 762205
1&1 now send a reminder before trying to obtain funds from your given debit/credit account. Did you receive this reminder?.