System failure

I bought a Money Transfer voucher on 29/08/23 at Grassy park post office. When the receiver tried to cash it, they said Pin was invalid. I then went back to GP post office and asked for a refund so that I could send the money another way. The clerk, Ms L Herbert said first that we must check pin and told me to punch it in. Whereupon their 'system' said Pin invalid again. I told her that it is impossible since I only use this one pin. I demanded a refund. She refused and said that she needs to email H/O first. Why I don't know. Well it's been a week now and still NO response from H/O.. I also sent multiple emails to the Post Office H/o and never received a response. I don't see why I cannot get my money back. The pin was for the benefit of the receiver to access the money. Since their system got it scrambled the receiver can't get it. However since I am the person who created this money transfer voucher, all I need to cash my money is producing my i.d. Which I did!! They will see that it corresponds with i.d. number on voucher and that's all proof that's needed to process my refund. Why can't the clerk, ms L Herbert acknowledge this??!! The fact that their 'System' couldn't pay out thousands of pensioners and Sassa grant recipients their money this month shows that their system is malfunctioning. I put the money in and I should be able to request a refund. That's it!