No response from Skywise

My son-in-law booked a flight on Skywise for he and my daughter from Cape Town to Johannesburg and paid with a credit card. They were due to fly on the 1st February 2016. When Skywise was grounded he had to purchase new tickets. His bank in the UK will not reverse the payment without a letter from Skywise confirming that they did not fly on that date. They only have until the end of this month (March) to make the claim and to date Skywise has been uncontactable, either by phone or email. They have ignored all request for a letter and time is running out.