Travelstart customer service is a nightmare

Once again trying to deal with Travelstart is a nightmare. I reported them in May 2022 then got a response.I am now trying to change my flights return date. They have all my correspondence on file and are still trying to overcharge me by a considerable amount. When I pointed that out to Zandile at 14.20 today, she said she has the correspondence from May however her Team leader is on lunch and they would call me back within a hour. To no avail. No one has bothered to call me. Dealing with Travelstart is terrible,customer service is totally non existent