Purchased car insurance online in July and paid full premium at that time.
Follow up communication requested proof of NCD and copy driving licences and warned of cancellation and fee of £75 if not complied with. Sent all three and received another letter saying not received and warning again of potential cancellation and fee. I knew they had been received as I'd sent them recorded delivery as suggested by eCar and had checked receipt online via Post Office. Sent them again just in case.
Received final communication advising policy cancelled two weeks prior to date of letter, £75 fee charged and minor refund (c£20 out of £137) to come. Despite writing letters to them I received no response, think I e-mailed as well but again no response.
Involved Financial Ombudsman and comparethemarket.com through whom I'd found eCar and eventually got the cancellation fee of £75 refunded thanks to their efforts (particularly comparethemarket.com who were great).
Check the similarities of this experience and that of Daniel Warriss who left review of eBike insurance on this site dated 10/04/11.