False advertising

Hi

I recently purchased a cover with a free screenguard for my phone from Vodacom Tygervalley. The screenguard however is too small for the phone (seems like a manufacturing fault) and the vodacom shop refused to replace it. Instead I was told i can buy a custom cut one for over R300. I was also told that the screenguard with the case was "free" clearly indicating that I should have expected it to be faulty. I've also contacted vodacom via Facebook messenger and they just direct me back to the shop.

As neither vodacom nor the actual store will assist me, could you please advise how I log this with yourselves?

Thanks

Phillip Kruger