Does not honor there promotions

They ran a promotion in March if you did a quote you would qualify for a R500 Woolworths Voucher, I took the time and effort to do the quote however they were more expensive. I enquired regarding the voucher and would be advised they will contact me. I followed up in April and was assisted by a rude sales manager who said I am only interested in the voucher. I advised him it is about the principal and honoring a promotion and that I also work in the insurance industry and we are held accountable for our promotions when we run them and would like my voucher. I followed up last week again no response?