They **** about the contract I was taking

Hello peter , on the 10th February 2018 I took a contract with telkom through istore, took two phones and specifically asked for closed plans, also known as hybrid and then I was given the phones. On Monday I needed to recharge my new phone and the airtime was rejected as the service provider says I didn't have the option to recharge, to my surprise I didn't understand why and therefore I called telkom and they explained to me that I was on an open plan. Haven read my contract I realized that it's not written open plan anywhere, so how can that be? I was then advised to go to istore to fix it since I took the phones through them. I had to first call the child who's got the other phone and probably calling on end right about now to ask them to stop as there's been an error made. I went to istore and they told me that telkom told them all their contracts are hybrids so they were as surprised as me and advised they can't do anything at this point since telkom is my service provider I must take it with them. I went back to telkom on Tuesday and they were closed as it was late and I went back Wednesday and they told me they can't change it on their system since they not the once who did the contract and they advised me to go to istore again. I went back with a print out that showed that the telkom system captured the contract as an open plan and as I got to istore, they had no other means to help me except apologize but say they can't do anything at this point. I can't afford an open plan as I had explained to them and I opted to return the phones since it's within 7days and cancel the contract then go open a new one with telkom themselves as they seem to have control of their system unlike istore. I was told I will be liable to pay the amount due to me this month end plus 20% of the original pricing of each phones as per their policy and I refuse to do so as am not the reason am terminating the contract. They made an error they won't admit, and am cancel this as they can't change it and opening one that I can afford. Am not blacklisted or have bad credit and am not about to start because people who don't know their jobs sit behind a counter. I need an advise as am going to take this further to protect myself. This is not as per the consumer protection act.