Buy & Get Voucher

I bought a new Samsung Fridge and received a Buy & Get voucher. After registering I did not receive the confirmation sms, so I send an email. They rep**** with a copy of the sms which to date I still have not received, on email, and confirmed that I need to phone a number and quote a reference number to choose my reward. I've been trying endlessly, but the phone number is always busy. I've also tried to complain via email, but to no avail, as phoning the phone number is the only way to choose the reward. It would be much appreciated if someone can get back to me regarding this.....