Requesting refund on money owed to me

BAD BAD BAD service. Opened an account 31 October to be able to purchase a cellphone. Was instructed to pay in 30% of the phone upfront. I paid in, only to discover phone has faulty factory issues. Decided to take a different phone, they requested another 30% payment , I refused and requested a refund which was denied.

I need my money back!! Head office insisted to purchase something worth that amount. I refuses. I need my money! Till today, no refund from them