Watsons App Coupon Not Working And Discount Missed

I am writing about a problem I experienced with a coupon in the Watsons app. On 18 December, I received a coupon code from the Nescafe app and tried to define and use this code in the Watsons application. However, the coupon could not be activated in the Watsons app and I was not able to use it. Because the coupon did not work, I also missed the campaign period of a product that was on discount at that time, so I could not purchase that product at the discounted price. I contacted customer service and was only told to try again, delete and reinstall the app, but despite these steps, the coupon still did not become active. I request that my coupon be activated or that another equivalent active coupon be defined for my account, and that I be informed as soon as this is done. In addition, I request to be able to purchase the relevant product, which was previously on discount, at the same discounted price by using this coupon.