False Promotions Advertising

Pick n Pay had a promotion where you get a stamp for every R100 you spend, these stamps are posted in a redeem/claim card where when you've reached a a certain number of stamps you receive a casserole

I filled in my card with 90 stamps (= R9000), went back to Pick n Pay Maponya mall where I but my groceries to redeem my price but was taken from pillar to post, ultimately I was informed to contact the Head Office to which I sent an email on their Complaints page but have not received any feedback till now

This is bad customer service because after filling in the stamps card I took time going to the shop and making calls to find out if the stock (casseroles) were available to this date I have not received my reward