6 months waiting for refund

Hi everyone, can someone help me to lodge a complaint against rain I bought the R479 wifi for my online learning they never delivered the sim card so I asked for a refund they said the purchase doesn't reflect on their side I gave them my banking details and proof of payment. It has been 5 to 6 months now they have been saying they are waiting for the billing department and they always ask for my banking details when I contact them. I have been calling them but no one picks up the phone on their support service and they are not replying to my emails also on Facebook. The last time I spoke to them over the phone about 3 weeks ago the lady told me she can see the transaction but she will have to consult with the other people on support services, she even asked me to confirm my details after that they never rep**** to me again. This really frustrates me.