I ordered a kids T-Shirt from Adidas South Africa last year around December, they claim to have delivered the package to the address i gave to them but no one says they have received it

I ordered a kids T-Shirt from Adidas South Africa last year around December, they claim to have delivered the package to the address i gave to them but no one says they have received it. I have been trying to communicate with them about it but every time I complain no one cares to follow through about it I'm at a point where they don't even bother replying to my emails anymore.