cellphone sold under false pretences

i was contacted last year not sure of date for a Sony Experia at R399 per month i was over the moon as i was blacklisted and desperately needed a cellphone so the phone was delivered to me so this phone will cost me R10000 it is not even worth R3000.00 i have had repairs done and i have had to spend money the phone keeps on rebooting i want a refund and stop my debit order and return the phone. what do i do they are no where registered or have a telephone number to call<br> regards<br> Debbie