PnP *****ing my money

I have been using PnP Brendwood since their opening and support them on a daily basis including my monthly groceries. On Thursday 15 March I bought stuff there, when the transaction showed accepted on my bank side but declined on PnP side, the casier run the transaction again. I went on to report this to the manager and he assured me the double transaction will be reversed within 48 hours. This morning I checked my account to find the transaction is still pending and I contacted my bank. They informed me to take the declined slip to my nearest branch to send to them in order to reverse the transaction. I called PnP Brendwood and explained the situation to the manager and said to him this will cost me money for taking off at work and travel cost including transaction cost. He said he will not reimburse me the money unless I give him bank statements prooving that the transaction has not been reversed. He further said he refuse to reimburse my loss of income as they don't work like that. At the end of the day it will cost me more than R300 to reverse a transaction of R162.97 The manager was at no help at all. This puts me at risk, doing my monthly groceries of average of R3000. What would I do if this has to happen again concidering I have a R4000 daily limmit on my card and it has been 4 days and nothing happened. This is how shops like PnP Brendwood ***** money from people and make it hard for those people to recover that money with the hope they will wright it off. This would definitely end my relationship with PnP Brendwood and associated brances as the management is arrogant and does not care whether they ***** customers money or not.