Poor customer service and overcharging

Suddenly got invoiced R20 more than what my agreement states for the last few months. While this isn't much it can add up over time. I have sent queries to find out why I have an extra charge as it doesn't show up on my invoice as well as attempted to log a faulty appliance. It's been nearly two weeks and all I have received is another invoice which still does not reflect the extra charge.

They are quick to bombard you with threats when your payment is a little late but when I asked for a full statement of account (about 5 months ago) as the amounts they were requesting wasn't making sense and I have yet to receive that either. Yet I have countless demands stating payments are late before the agreed upon payment date has arrived. Horrible customer service and threats is not how you make happy customers.