Advantage taking from the people working at cartrack

There is a man from this company i had a disput with now he makes sure am 1000% sure its him who does a collection call at 06:10 am when you call to ask about accounts at 6pm they tell you operation hours for accounts its 8-5 I consolidate my contract with them twice now am on a month to month account i pay when i need cover that simple am no longer renting a unit from its mine how ever not the issue they called me previous day at 7am told them please call after 12 they did no such thing instead they called continuously for 5-8times after notifying them about my unavailability at that moment i colud bot work fir 45mins because they kept calling somebody please help me report these people or speak to management i can not tolerate such infact i need to persue a case of harresment