Refund owed for returned goods. never paid to me

I bought a bunch of tiles from Tile Africa randburg. Because i paid via EFT, when i returned the goods to the store, they could not refund me, but told me it had to go to their head office for refund. so of course i wrote down my bank details. But that was in October. i have not seen any amount refunded to me. And they do not respond to their emails or even acknowledge receipt. i don't know how to get hold of the head office.