1/3 of transactions have problems over busy xmas season

During our peak holiday season transactions had to be tiped in several times with a variety of fault messages. Some transactions were then charged multiple times to customers account. Others the customers left the shop after the ikokha device said the transaction was approved and then later it turned out the transaction failed . I lost that money. I have been told the technical team will look in to the issue by 3 customer service agents. I have not had any feedback.