POOR NETSTAR AFTER SERVICE REGARDING REFUNDS

I bought a car last year which came with a tracker. I was only informed once they called to find out the details for fitment of the tracker. I was then covered from the 30th of April 2018. I sold my car this year in March, and the lady from the dealer assisted me with the cancelation of the tracker. But then all my problems started with this *********** company. After a vey long time , someone finally came back to me. We paid 36 months in advance, but only used 11 of the 36 months. When we finally received a sort of refund, it was not what I have worked it out to be. A lady from the finance department then phoned me, and after explaining, she wasn't even sure about what to explain to me, but then said that I would only be refunded for the months I used Netstar. I find this totally unacceptable. I want the full refund for the 24 months we did not use. The Mrs Naidoo from the finance department said that she will find out further and would have come back to me with the correct detail about the refund , but to date no one has come back to me. Even the lady from the dealer is struggling to get correspondence from anybody at Netstar. I am very disappointed in Netstar and will definitely not recommend anybody to make use of this company as they only choose when to respond to their customers.