Payjoy is Terrible

So my son went to a Jet Store in Saturday lastweek to purchase or do enquiry on purchasing a cellphone.He was told about Payjoy.Half of the info he did not understand.The highlight is that the phones original price is R3500 and they sell it to you for R8500.Day light *******.He was told to pay an amount of R689 and then another R200 When he spoke to me i contacted the store.I told my son he should cancel becoz according to the CPA if you didnt understand that you will be in a debt trap of almost R900 per month.Payjoy flat out refuss to refund the monies paid.When the CPA is clear that consumer has the right to return item during the cooling off period and receive full refund.My son has been up and down to Store and only today they decide to cancel but refuse to pay back the money.I will be taking this matter to the CGCSA.Its ******* practice this.