Network Solutions Lack of refund Internet

We agreed to a month to month internet hosting contract with Network Solutions for our company.  When we sold the company, they were informed of the sale and that the new owners would be changing hosting provider.

They continued to charge my credit card for approximately fifteen months for the monthly fee.  Shame on me for not noticing it, but when informed of the error, they agreed the problem was on their end and were to issue a full refund.

A month later my statement showed a credit for 1 month of service and when contacted no one could provide answers as to why only one month was refunded but they considered the case closed.