You need to initially write to carphone customer services, requesting the return of all insurance premiums that have been inadvertently deducted since the contract was ended.
Your letter should state that when the contract ended, it is only reasonable to expect that all the other associated insurance deductions would have ceased at the same time, as there could not possibly have been any benefit whatsoever in you still paying insurance on a contact that had been terminated....send communication by recorded delivery.!
Failing there willingness to play fair and return all insurance premiums, inform them it is your intention after eight weeks to lodge a complaint about their unfair practice with the insurance ombudsman at the FOS below.
http://www.financial-ombudsman.org.uk/consumer/complaints.htm