Delivering stress, appalling customer service and withholding money - right to your doorstep!

Really unacceptable customer service. I started a new business that required a courier service in December 2020. Filled out all the necessary forms, and within a week, had spent thousands of rands on deliveries. All went well for the first two weeks, but then they failed to pitch to pick up packages or communicate why for days on end. This happened on two separate occasions, and when I expressed my disappointment - no apology, no comms in fact for another few days. The whole system is far more expensive (more than double), unpredictable and time consuming than their competition (which I have since moved to and been only happy with). As they work on a pay-before-they-do-anything system, your account has to have thousands of rands in it before you can even place an order. As such, I am still waiting for them to reimburse me the money they legally owe me, that I did not use but had put in my account beforehand. Since early Jan, I've been requesting this and they agree to refund it, but 3 month later, and countless mails sent to them, and still nothing.