Complain i wish i never did business with that company

On the 10th june 2020 i bought two items from new world menlyn which are satelite signal finder and smart lnb. So 3days later i retund the smart lnb "still cealled never been used" so i was told they can't refund me the money the can only give me a voucher to use in the store. I don't need the voucher coz the nothing i want to buy in the store at the moment i just need my money coz i bought those items cash not with credit. I was told that day that their company policy say THEY DONT OFFER CASH FOR RETURNS ONLY VOUCHER TO USE IN THEIR STORE. PLEASE HELP I NEED MY MONEY REFUND