*** service and lack of Communication with clients

I installed a car Tracker with netstar 2017 I paid for 2017 . In 2018 moved to oudtsoorn changed my bank didn't get any updates from Netstar no SMS no emails no calls only to find out today that my account was outstanding with but they never called to inform me nor sms or email what suprise me is I was paying R120 last payment January 2018 now I'm told that I'm behind by 7000 to me that doesn't add up because I was never contacted only today they called to say they handing my account to ITC . If pay them they must send statements showing where that 7000 comes I don't mind paying I need clarity first I would understand if it was 3000 not 7000 nop I was paying R120 for crises sake and no calls or emails to inform me were sent