Invalid voucher

Every month the Pep page on Facebook has a Samsung competition where you get to win R500 Pep voucher. In May 2023 I entered the competition and I won. My voucher was sent to me and the next day I went to pep to use my voucher and I get there they tell me that my voucher is invalid because it's missing 1 number. It had 12 numbers when it was supposed to be 13 numbers. So I called customer service on the 10th of May and they asked me to send an email with my details and the sms I received with the voucher. I did all that and today it's the 25th July and nothing has been done about my issue. I send emails almost every week to get an update but I don't get a response. When I do get a response it's an automated email saying my ticket is closed. The people on the Pep page don't respond either. I am so disappointed because I thought this would have been resolved before my birthday in June so I can spoil myself with winter clothes but that didn't happen. I'm unemployed so the voucher was a very welcome surprise for me. My heart is actually aching and I'm actually shedding a tear as I write this.