BAD SERVICE FROM THE STORE

I was at a jet store last wed on the 25th to buy some items. when I got to the till the cashier told me that her system is slow & has been freezing. I then gave her my bank card to pay. I punched in my pin & she said it didnt go through,she asked for my card again & I gave her in which I had to punch in my pin again.as I left the shop I received 2 sms's that the transaction went twice & my available balance changed. I then went to the store the following day to report this.thats when I was so frustrated about the service I got. I got in & asked this lady who was complaining & shouting at customers as to who can I talk too. she said to me I should go look for the manager as she does not deal with this things. I walked around the whole shop looking for a person by the name of Alice or Elisa,to which when I found Elisa she also said she does not deal with this things I should go the tills & ask to see Joyce. that time I have spent around 30minz looking for someone to help me. this Joyce person said she too cant help me coz I don't have a bank statement, I must go to the bank & come back Only then I can get help. I did that & went 2 the shop but up to now I still haven't heard from.