Poor service

Hello I did a purchase of shoes at rage Ballito on the 7th of September at 17:28 and at 6 went back to do an exchange because as I have issue on my leg so one shoe was fitting right and the one is big so I took size 7 and when I got home I've discovered that the shoe is it's painful on my injured leg so I went back the following day to do exchange only find that they said there system is offline they can't pick up the transaction they told me to come back Monday when the manager in working Monday I went there again and the manager told me the same thing they told me on Saturday and she took down my detail and promised to call me once system is sorted she never called me Tuesday,Wednesday until I decided to go back again today and she told me that they can't assist because they having load shedding and I told her I'm gonna come back once load shedding is finished and she Dan sent me the voice note on WhatsApp to tell me that they can't assist me because I have done the exchange before and their system only allow 1 exchange.I called her and tell her that I'm coming back to the store and when I got there she told me the same thing and I then asked her why she's telling me something they is not mentioned on their slip and all the terms written on their slip it's saying 7days and in original condition and nothing it's saying"Only 1 exchange is allowed "Why all those terms are not written on their slips and we customer don't know that ,slip at the back it's blank that means all those terms can be written on it.