Bad service

I am a single mother who works hard to pay my bills every month, I got a phone call from a staff member, saying I owe my sars 7k over a period of time, I asked if I can have a updated statement, as my efiling say I owe 0, I then told them I will not pay a cent till I got the statement not only did they harass me and phone me 5 times every hour, but then started calling my mother, after two months of fighting they sent the statement to my mother saying I owe 1750 so and I would I sent another R500 as promised and because of the showing how much I owe, so last week I got a call from one of there call center agent or employee saying I need to pay my sars or they will take action he was rude, I told him I made a payment plan with a lady from there company to pay 500 a month she accepted it and did so, the Guy told me I have never made payment and doesn't care that I'm a single mom, he was not professional, could give my up dates nor how much I have paid