Useless phone on upgradw

We received a call from Cell C Direct advising of special of specials available on upgrade. The package was suitable to my needs and at a good price. I was told that the a Samsung J5 upgrade 2017 model with 16GB expandable memory and dual sim which was similar to the AG Ghost I was using. However I received a Samsung J5 with only 8GB memory which I can not use as the memory is permanently full . I have been into Cell shops but they say they can not assist as the upgrade was done with Cell C Direct. So I have a new contract which I can not fully utilise as the phone is not fit for purpose.