Astounding disrespect for customer

Made the mistake to buy putty from Buco, Rietpan, Benoni. Took 3 bags, 5kg, 2 kg and 1 kg respectively. Went through till, paid for the goods and went to end control to leave who noticed that the till slip was different to the goods I had. Till operator had made a mistake, NOT ME! I was asked to follow the guy all the way to the other end where I was to be given a credit for one 1kg packet and I must go through the whole process again for a R12.00 ish packet, which i must pay on a cheque card. I refused and simply wanted a refund, why should I go through all this nonsense due to THEIR mistake (R5 ish). Refund request was accepted but the paperwork and authorisation was simply ridiculous, went to 3 separate departments, 2 of which had to run off to get authorisation. A simple R5.00 mistake on their behalf, took them 20 plus minutes to sort out, leaving me late for an appointment with a client. The staff were very unfriendly until I got an apology from the 4th person I had to deal with. I realise I did make a mistake by going to Buco in the first place. Knowing the terrible service to expect going forward it will be my LAST visit.