Altech Netstar daylight ******s

In March 2015, I agreed for Altech to upgrade my vehicle tracking system with the understanding that the old system account would be deactivated and I will be only charged for the new system. Unbeknown to me, Altech charged me for the new and old system for 36 months. 2 weeks ago, I discovered that I was being double charged when Altech offered me another upgrade. On further discussion with Altech, it agreed that I was double charged and should be refunded. However today, Altech informed that their policy only allows for 18 months refund and they are not prepared to refund me for the full 36 months. So basically Altech is robbing me of 18 months of installments because I am the small guy and cannot afford attorneys. I find Altech's actions lack ethnics and fairness.