Travelstart customer service NON EXISTENT

In 2020 I bought an international ticket for my son to travel to France. I specifically took out Covid insurance. As predicted my son was unable to travel. We are now trying to rebook his flight and we cannot get hold of a single person at Travelstart to assist. We have sent numerous emails, whatsapps, phone calls (always unanswered) I have gone onto their social media pages and sent messages???? To no avail! The insurance allowed usto rebook the flight up to 2 years later. This will expire at the end of April. My son needs to be in France by the 26th of April and we still cannot the book his ticket? How is it possible that their customer service can be this atrocious???