cash back Refund

Worst customer service ever! last year November I purchased R 32 000 building material from Discount build Dube village branch , a month later I requested a refund of roofing material since it doesnt meet my requirements. the total amount of a refund requested is R12 200. Now sales asssistant and the manager is forcing me to credit me a voucher instead of cash back refund. And when I asked for head office contact number , Sizwe Gina the sales assistant said he is not allowed to give out head office number to customers.

Please note the material that I am referring to is still in store.