Bad customer service

So...this morning I went to Woolies for a cup of coffee,I asked the barista if their card machine does tap to pay,I was to told yes they do after two transactions which declined and I know for a fact I have sufficient funds.each decline cost me about R10 and the coffee cost about R24.a supervisor was called to sort out this problem and failed to do so,I was than told,sometimes the machine does this and I was made to leave without my coffee,which is really unfair if you ask me.thnx Woolies,you lost a customer and yes I will close my account.