This will be assuming you meant physical damage coverage when you said "full coverage." If your policy generated a credit or refund when you lowered your coverages, you should be given credit for the extra funds. If you still owe on your policy, most insurance companies will apply the resulting credit to your remaining balance/payments. If there is no remaining balance, before or after, the credit is applied, this will result in a refund to the insured. If you have a refund due to you, you will want to contact your insurance company to find out what their procedure is to disperse refunds. (While you are talking to your insurance company, you can make sure they processed the change to your policy. Because, if the change has not been processed, it can obviously lead to a delay in processing the credit/refund.)