Showmax data issue

Dear Vodacom. Although I appreciate the free 5GB data you gave me as a 'goodwill gesture', you have neither understood nor resolved my issue. On 30/12/2018 I signed up for Showmax using my Voda SIM. According to your advertising, you will give users 5GB of data per month for 3 months for streaming. After completing the registration process, I received a confirmation SMS: 'Thank you for your purchase. Your video data bundle has been allocated. You can now start watching the movie.' So I started watching a movie. But my normal data was being depleted and not the free 5GB Showmax data. I logged the call with customer care, a very helpful and friendly lady advised that it had to be assigned to a technician. This is the response I received: 'Dear customer an investigation has been completed on 079.......... As a valued customer of Vodacom and as a Once off Gesture of Goodwill, Vodacom has loaded a credit of 5GIG anytime data bundle for the challenge experienced. It may be significantly helpful to install the My Vodacom APP in order to constantly manage and assess the usage on your number. We apologize for any inconvenience caused. Kind regards, Vodacom Customer Care.' I already have the app on my phone, that's how I was able to see that my normal data was being depleted and the Showmax data remained untouched. Please can you resolve my query properly. Thanks.