Dischem not honoring rain checks

I was looking for Dischem Gold Co enzyme 160mg about a month ago, It was on special listed as R134,95 but there was no stock available... I went to N1 city Dischem to write my name in the Rain check book to offer product when in stock again and so expect to pay the price of promotions as they couldn't assist me. Got a call today that product is available but they not willing to give the price to me again as I requested and assumed and was told i will pay when they get stock.