Street Fever = Bunch Of ******! Worst service ever!

I made an online purchase on the street fever website on Monday 2nd December 2019. I paid R500 for a pair of sneakers and received an email from street fever saying that my payment has been received and that my order would be processed soon. A few days later they e-mailed me saying that I need to make a payment or my order would be cancelled. I called them and tried emailing and they said they couldn't track my payment, which according to them means that I did not make any payment. And unless I send them proof of payment they cannot assist me. I emailed them my bank statement as proof, because when I went to my bank I was told that I could not get a proof of payment as the purchase was not made from my account as an eft or internet banking transaction (by adding the recipient as a "beneficiary"), but it was processed directly on Street Fever's website. However, they advised that I should email my bank statement as proof. I did that and Street Fever refused to accept it as such. What can I do? Street fever sent me an email today (09 December 2019) saying that they have cancelled my order due to none payment. But when I made the purchase, I received an sms that money was deducted from my account by street fever and my bank statement also reflects the payment that I made to street fever. I have the proof but due to incompetence I am expected to just to write off my R500?? I asked if my bank can't reverse the transaction and they said it'll cost me about R150 for the reversal and that I would have to pay that R150 regardless of whether or not the reversal was successful. So I stand to lose an additional R150 in the process?? I'm literally at my wit's end. I have been calling and sending emails back and forth to street fever. Their phones are either engaged 99% of the time and you don't get through or their email responses are weak and also extremely delayed. I'm in desperate need of some help or advice on how I can go about getting my money back from these people.