Let Down Again and I'm not even surprised anymore.

So I make a purchase with Takealot, for a product on special that gives you 4 boxes as part of that deal. Package is delivered, sealed from them when I opened it, but 2 boxes are missing. I make contact for them tpo send the missing boxes as I'd started making use of my purchase. After almost a week of back and forth on emails explaining the same thing, they asked me to bring the items back so they can "investigate". My advice is, I'm continuing to use the items they delivered, they must investigate and tell me the outcome, their response is "we cannot investigate without the items you are using".