MTN **** OR ADVERTISING PLOY?

I bought a R199 data bundle. Received 2G (daytime) and 2G (night time). Then bought a R79 two week bundle for WhatsApps only. I still had 6Gigs of data for night viewing, which MTN Plett at Marshal Square confirmed were available. After I had downloaded and viewed 2 or 3 videos I checked my data. The gigs had not changed at all and are still 6Gigs. The downloads had used my newly loaded R79 data bundle. Question- are the night gigs a **** or advertising ploy? My daytime is less 20mb now. As I amon a social grant, MTN needs to give me a reason for not using the gigs they had provided, which was confirmed as such by their store inPlett.