Unfair and Unacceptable

I purchased a lounge suite from Joshua Dore that cost me 17000 round about .The amount outstanding was R3000 that i had to pay and if the insurance would have paid out that would have another R3000 in total i owed them R6000 i skipped 2 months the year before i was retrenched my money weren't paid into my account due to reasons...afterwards i made arrangements to pay the extra on the account per month for the money that was in arrears + my installment if it weren't like that i would have been fully paid and few months later i was retrenched.I took a copy of my retrenchment letter in and signed the required forms. I obviously had insurance on the contract and until this day they are still harassing me for payment and not only that..... Why does one take insurance out if they have no intention of paying out! I need help, I don't know where to turn anymore!!! PLEASE HELP!!!