Refund on Overpayment

I was on the Verizon One Bill plan for a few years until one day the plan was dissolved without alerting me to it so my online payment for both mobile and home services, went only to home services. Verizon Wireless wondered where my payment was and Verizon home, said they would refund it but haven't done so yet. Anyone else have this problem. How can I find out if the refund every happened?