Please help

My name is Masilu Joseph Sekhutudi,I had a contract with a cartrack last year (2016) but within three months of the contract I was involved in a serious car accident so I had to go to Tzaneen branch to do the cancellation, I was told that I will have to pay R1700.00 for cancellation or I can pay R850.00 and their technician can come to the car and remove the device. So I took the technician route and later on I received an e-mail confirming that my contract is been cancelled. But now I'm surprised to be receiving an sms that shows my account is in arrears. 'Cartrack Account is in Arrears with R2078.00.Contact Sthembiso Sitole at ********** 398. Ignore if payment has been made.' Please help me.

Regards Joseph