Router return refund

I was a fixed LTE customer at Supersonic, and then cancelled the service after a year. The cancellation consultant provided me with an address to ship the router to, the router was delivered to Supersonic within the required time period. However, I got a debit order for R2500 against my name. I’ve now been waiting for almost 3 weeks after a case number has been opened for a refund. Earlier a week a consultant put down the phone in my ear after she put me on hold for 4 minutes, and all other enquiries have been futile. I have never in my life experienced such bad customer service and dishonest business practice from a company.